RFR: 8369393: NMT: poison the canaries of malloc header under ASAN build

[Afshin Zafari]

NMT can detect malloc'd memory corruption using canary tests at header and footer of every memory region. This can only be done at free time of the memory where NNT checks the canaries and report error if they are not as expected.
In this PR, the canary parts also are poisoned using ASAN API to get notified whenever a read/write op is done. on the canary parts. `_size` member of the malloc header is also poisoned, since it is used for finding the footer address.

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Commit messages:
 - 8369393: NMT: poison the canaries of malloc header under ASAN build

Changes: https://git.openjdk.org/jdk/pull/27685/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27685&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8369393
  Stats: 177 lines in 5 files changed: 154 ins; 0 del; 23 mod
  Patch: https://git.openjdk.org/jdk/pull/27685.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27685/head:pull/27685

PR: https://git.openjdk.org/jdk/pull/27685