Enable glibc memory debugging in CI to catch heap corruption early

Set MALLOC_CHECK_=3 to abort immediately on heap corruption detection
without error messages. Values: 0=ignore errors, 1=print diagnostics
to stderr, 2=call abort(), 3=abort without diagnostics.

Set MALLOC_PERTURB_=170 (0xAA) to fill allocated memory with 0x55 and
freed memory with 0xAA, exposing use-after-free and uninitialized
memory bugs through deterministic non-zero patterns.

Author: lovasoa

.github/workflows/test.yml

@@ -4,6 +4,8 @@ on: [push, pull_request]
 
 env:
   CARGO_TERM_COLOR: always
+  MALLOC_CHECK_: 3  # Abort immediately on heap corruption (0=ignore, 1=print, 2=abort, 3=abort+no messages)
+  MALLOC_PERTURB_: 170  # Fill allocated memory with 0x55, freed memory with 0xAA to catch use-after-free
 
 jobs:
   format: