RFR: 8324781: runtime/Thread/TestAlwaysPreTouchStacks.java failed with Expected a higher ratio between stack committed and reserved

[Liming Liu]

The testcase failed on Oracle CI since JDK-8315923. The root cause is that Oracle CI runs Linux-5.4.17-UEK where the value of MADV_POPULATE_WRITE (23) is used as MADV_DONTEXEC which is not supported by upstream. This PR solves the testcase failure by checking the support of (MADV_POPULATE_WRITE_value + 1) for UEK releases.

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Commit messages:
 - Detect UEK releases and adjust the detection of MADV_POPULATE_WRITE accordingly

Changes: https://git.openjdk.org/jdk/pull/18417/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18417&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8324781
  Stats: 54 lines in 3 files changed: 35 ins; 7 del; 12 mod
  Patch: https://git.openjdk.org/jdk/pull/18417.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18417/head:pull/18417

PR: https://git.openjdk.org/jdk/pull/18417