RFR: 8324781: runtime/Thread/TestAlwaysPreTouchStacks.java failed with Expected a higher ratio between stack committed and reserved [v8]

[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 versions of kernels first, and checking the availability of MADV_POPULATE_WRITE when they are not older than 5.14.

Liming Liu has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains eight commits:

 - Merge branch 'master' into 8324781
 - Mention the number in comments
 - Use kernel_version
 - Mis-removed the two lines
 - Parse kernel versions alone
 - Disable UseMadvPopulateWrite when not supported
 - Exit early in os::pd_pretouch_memory and generate a warning when user turns on UseMadvPopulteWrite when not supported
 - Check kernel versions before check the support of the advice

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Changes: https://git.openjdk.org/jdk/pull/18592/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18592&range=07
  Stats: 64 lines in 2 files changed: 40 ins; 20 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/18592.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18592/head:pull/18592

PR: https://git.openjdk.org/jdk/pull/18592