RFR: 8369393: NMT: poison the malloc header and footer under ASAN build

[Afshin Zafari]

Under ASAN builds and when NMT is enabled, the header and footer of MallocHeader are poisoned/unpoisoned at malloc/realloc/free times.
Checking the integrity of memory blocks is off under ASAN builds.

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Commit messages:
 - 8369393: NMT: poison the malloc header and footer under ASAN build

Changes: https://git.openjdk.org/jdk/pull/28503/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=28503&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8369393
  Stats: 122 lines in 5 files changed: 108 ins; 8 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/28503.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28503/head:pull/28503

PR: https://git.openjdk.org/jdk/pull/28503