LocaleLowercase in MagickCore/locale.c in ImageMagick before 7.0.8-32 allows out-of-bounds access, leading to a SIGSEGV.
### Prerequisites

- [ Y ] I have written a descriptive issue title
- [ Y ] I have verified that I am using the latest version of ImageMagick
- [ Y ] I have searched [open](https://github.com/ImageMagick/ImageMagick/issues) and [closed](https://github.com/ImageMagick/ImageMagick/issues?q=is%3Aissue+is%3Aclosed) issues to ensure it has not already been reported

### Description

```C
1522 MagickExport int LocaleLowercase(const int c)
1523 {
1524 #if defined(MAGICKCORE_LOCALE_SUPPORT)
1525   if (c_locale != (locale_t) NULL)
1526     return(tolower_l(c,c_locale));
1527 #endif
1528   return(tolower(c));
1529 }
```

The parameter `c` missing check in function LocaleLowercase, which may lead to out-of-boundary vulnerability.

### Steps to Reproduce
https://github.com/Dk0n9/MyFuzzy/blob/master/oob_LocaleLowercase_crash

`magick convert oob_LocaleLowercase_crash /dev/null`

In the gdb:
```
Stopped reason: SIGSEGV
0x00007ffff6ddd857 in __tolower_l (c=0x14f3cf, l=0x7ffff7197960 <_nl_C_locobj>)
    at ctype_l.c:42
42	in ctype_l.c
2: c_locale = (volatile locale_t) 0x7ffff7197960 <_nl_C_locobj>
gdb-peda$ bt
#0  0x00007ffff6ddd857 in __tolower_l (c=0x14f3cf, l=0x7ffff7197960 <_nl_C_locobj>)
    at ctype_l.c:42
#1  0x00007ffff777f8ac in LocaleLowercase (c=0x14f3cf) at MagickCore/locale.c:1526
#2  0x00007ffff782a575 in GlobExpression (
    expression=0x7ffffffedf82 "\365\217\217\217\217MMa\\-d-\n", 
    pattern=0x7ffff7a8bb98 "EPSF-*", case_insensitive=MagickTrue)
    at MagickCore/token.c:544
#3  0x00007ffff782a0af in GlobExpression (
    expression=0x7ffffffedf82 "\365\217\217\217\217MMa\\-d-\n", 
    pattern=0x7ffff7a8bb98 "EPSF-*", case_insensitive=MagickTrue)
    at MagickCore/token.c:411
#4  0x00007ffff795385e in ReadPSImage (image_info=0x555555775d60, 
    exception=0x55555576ab10) at coders/ps.c:617
#5  0x00007ffff769f8fa in ReadImage (image_info=0x555555772a70, 
    exception=0x55555576ab10) at MagickCore/constitute.c:547
#6  0x00007ffff76a0fe3 in ReadImages (image_info=0x55555576f780, 
    filename=0x555555769bb0 "./crash", exception=0x55555576ab10)
    at MagickCore/constitute.c:917
#7  0x00007ffff72163a1 in ConvertImageCommand (image_info=0x55555576f780, argc=0x3, 
    argv=0x55555576a190, metadata=0x7fffffffbc10, exception=0x55555576ab10)
    at MagickWand/convert.c:644
#8  0x00007ffff72e9d0f in MagickCommandGenesis (image_info=0x55555576c490, 
    command=0x7ffff72150f2 <ConvertImageCommand>, argc=0x3, argv=0x7fffffffdf90, 
    metadata=0x0, exception=0x55555576ab10) at MagickWand/mogrify.c:184
#9  0x0000555555555347 in MagickMain (argc=0x3, argv=0x7fffffffdf90)
    at utilities/magick.c:149
#10 0x0000555555555484 in main (argc=0x4, argv=0x7fffffffdf88)
    at utilities/magick.c:180
#11 0x00007ffff6dceb97 in __libc_start_main (main=0x555555555464 <main>, argc=0x4, 
    argv=0x7fffffffdf88, init=<optimized out>, fini=<optimized out>, 
    rtld_fini=<optimized out>, stack_end=0x7fffffffdf78) at ../csu/libc-start.c:310
#12 0x000055555555504a in _start ()
```

### System Configuration

- ImageMagick version: ImageMagick 7.0.8-30 Q16 x86_64
- Environment (Operating system, version and so on): Ubuntu 18.04
- Additional information:

Credit: dk from Chaitin Tech

Out-of-boundary in function LocaleLowercase of MagickCore/locale.c
This is a GitHub Issue
repo:ImageMagick
owner:ImageMagick
Title : Out-of-boundary in function LocaleLowercase of MagickCore/locale.c
Issue date:

--- start body ---
### Prerequisites

- [ Y ] I have written a descriptive issue title
- [ Y ] I have verified that I am using the latest version of ImageMagick
- [ Y ] I have searched [open](https://github.com/ImageMagick/ImageMagick/issues) and [closed](https://github.com/ImageMagick/ImageMagick/issues?q=is%3Aissue+is%3Aclosed) issues to ensure it has not already been reported

### Description

```C
1522 MagickExport int LocaleLowercase(const int c)
1523 {
1524 #if defined(MAGICKCORE_LOCALE_SUPPORT)
1525   if (c_locale != (locale_t) NULL)
1526     return(tolower_l(c,c_locale));
1527 #endif
1528   return(tolower(c));
1529 }
```

The parameter `c` missing check in function LocaleLowercase, which may lead to out-of-boundary vulnerability.

### Steps to Reproduce
https://github.com/Dk0n9/MyFuzzy/blob/master/oob_LocaleLowercase_crash

`magick convert oob_LocaleLowercase_crash /dev/null`

In the gdb:
```
Stopped reason: SIGSEGV
0x00007ffff6ddd857 in __tolower_l (c=0x14f3cf, l=0x7ffff7197960 <_nl_C_locobj>)
    at ctype_l.c:42
42	in ctype_l.c
2: c_locale = (volatile locale_t) 0x7ffff7197960 <_nl_C_locobj>
gdb-peda$ bt
#0  0x00007ffff6ddd857 in __tolower_l (c=0x14f3cf, l=0x7ffff7197960 <_nl_C_locobj>)
    at ctype_l.c:42
#1  0x00007ffff777f8ac in LocaleLowercase (c=0x14f3cf) at MagickCore/locale.c:1526
#2  0x00007ffff782a575 in GlobExpression (
    expression=0x7ffffffedf82 "\365\217\217\217\217MMa\\-d-\n", 
    pattern=0x7ffff7a8bb98 "EPSF-*", case_insensitive=MagickTrue)
    at MagickCore/token.c:544
#3  0x00007ffff782a0af in GlobExpression (
    expression=0x7ffffffedf82 "\365\217\217\217\217MMa\\-d-\n", 
    pattern=0x7ffff7a8bb98 "EPSF-*", case_insensitive=MagickTrue)
    at MagickCore/token.c:411
#4  0x00007ffff795385e in ReadPSImage (image_info=0x555555775d60, 
    exception=0x55555576ab10) at coders/ps.c:617
#5  0x00007ffff769f8fa in ReadImage (image_info=0x555555772a70, 
    exception=0x55555576ab10) at MagickCore/constitute.c:547
#6  0x00007ffff76a0fe3 in ReadImages (image_info=0x55555576f780, 
    filename=0x555555769bb0 "./crash", exception=0x55555576ab10)
    at MagickCore/constitute.c:917
#7  0x00007ffff72163a1 in ConvertImageCommand (image_info=0x55555576f780, argc=0x3, 
    argv=0x55555576a190, metadata=0x7fffffffbc10, exception=0x55555576ab10)
    at MagickWand/convert.c:644
#8  0x00007ffff72e9d0f in MagickCommandGenesis (image_info=0x55555576c490, 
    command=0x7ffff72150f2 <ConvertImageCommand>, argc=0x3, argv=0x7fffffffdf90, 
    metadata=0x0, exception=0x55555576ab10) at MagickWand/mogrify.c:184
#9  0x0000555555555347 in MagickMain (argc=0x3, argv=0x7fffffffdf90)
    at utilities/magick.c:149
#10 0x0000555555555484 in main (argc=0x4, argv=0x7fffffffdf88)
    at utilities/magick.c:180
#11 0x00007ffff6dceb97 in __libc_start_main (main=0x555555555464 <main>, argc=0x4, 
    argv=0x7fffffffdf88, init=<optimized out>, fini=<optimized out>, 
    rtld_fini=<optimized out>, stack_end=0x7fffffffdf78) at ../csu/libc-start.c:310
#12 0x000055555555504a in _start ()
```

### System Configuration

- ImageMagick version: ImageMagick 7.0.8-30 Q16 x86_64
- Environment (Operating system, version and so on): Ubuntu 18.04
- Additional information:

Credit: dk from Chaitin Tech

--- end body ---
