Virtuoso 7.2.12 crashes at  `MD5_Final` when calling the `MD5_FINAL` function.

Sometimes, the server doesn't crash directly, but its memory usage rapidly increases, eventually leading to Out Of Memory (OOM). **So the memory usage of the process `virtuoso-t` should be noted when reproducing the bug.**

Environment: Ubuntu 20.04, docker image `openlink/virtuoso-opensource-7:7.2.12`.

PoC:
```sql
SELECT MD5_FINAL(REPEAT('1', 200));
```
Backtrace (**sometimes the server doesn't crash but OOM**):
```
#0 0x7f5eab53291c (MD5_Final+0xfc)
#1 0xa2441e (bif_md5_final+0x9e)
#2 0x755674 (ins_call_bif+0xc4)
#3 0x75d402 (code_vec_run_v+0x25f2)
#4 0x7b980f (qn_input+0x38f)
#5 0x7b9cb6 (qn_send_output+0x236)
#6 0x82c49d (set_ctr_vec_input+0x99d)
#7 0x7b984e (qn_input+0x3ce)
#8 0x7cb03b (qr_exec+0x11db)
#9 0x7d89d6 (sf_sql_execute+0x11a6)
#10 0x7d94de (sf_sql_execute_w+0x17e)
#11 0x7e219d (sf_sql_execute_wrapper+0x3d)
#12 0xe2aa3c (future_wrapper+0x3fc)
#13 0xe3233e (_thread_boot+0x11e)
#14 0x7f5eab39c609 (start_thread+0xd9)
#15 0x7f5eab16c353 (clone+0x43)
```
Virtuoso 7.2.12 crashes with the `MD5_FINAL` function
This is a GitHub Issue
repo:virtuoso-opensource
owner:openlink
Title : Virtuoso 7.2.12 crashes with the `MD5_FINAL` function
Issue date:

--- start body ---
Virtuoso 7.2.12 crashes at  `MD5_Final` when calling the `MD5_FINAL` function.

Sometimes, the server doesn't crash directly, but its memory usage rapidly increases, eventually leading to Out Of Memory (OOM). **So the memory usage of the process `virtuoso-t` should be noted when reproducing the bug.**

Environment: Ubuntu 20.04, docker image `openlink/virtuoso-opensource-7:7.2.12`.

PoC:
```sql
SELECT MD5_FINAL(REPEAT('1', 200));
```
Backtrace (**sometimes the server doesn't crash but OOM**):
```
#0 0x7f5eab53291c (MD5_Final+0xfc)
#1 0xa2441e (bif_md5_final+0x9e)
#2 0x755674 (ins_call_bif+0xc4)
#3 0x75d402 (code_vec_run_v+0x25f2)
#4 0x7b980f (qn_input+0x38f)
#5 0x7b9cb6 (qn_send_output+0x236)
#6 0x82c49d (set_ctr_vec_input+0x99d)
#7 0x7b984e (qn_input+0x3ce)
#8 0x7cb03b (qr_exec+0x11db)
#9 0x7d89d6 (sf_sql_execute+0x11a6)
#10 0x7d94de (sf_sql_execute_w+0x17e)
#11 0x7e219d (sf_sql_execute_wrapper+0x3d)
#12 0xe2aa3c (future_wrapper+0x3fc)
#13 0xe3233e (_thread_boot+0x11e)
#14 0x7f5eab39c609 (start_thread+0xd9)
#15 0x7f5eab16c353 (clone+0x43)
```
--- end body ---
