RFR: 8306279: Build failure after JDK-8299592

[Daniel Jeliński]

Please review this patch that disables a warning that appeared on linux builds in slowdebug configuration after [JDK-8299592](https://bugs.openjdk.org/browse/JDK-8299592).

I plan to investigate why this failure appears only in slowdebug mode; this patch is intended to unblock the CI.

Verified that the slowdebug builds pass with this patch applied.

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Commit messages:
 - Disable debug mem warning

Changes: https://git.openjdk.org/jdk/pull/13507/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13507&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8306279
  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/13507.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13507/head:pull/13507

PR: https://git.openjdk.org/jdk/pull/13507