RFR: 8324781: runtime/Thread/TestAlwaysPreTouchStacks.java failed with Expected a higher ratio between stack committed and reserved [v2]

[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 incrementally with one additional commit since the last revision:

  Exit early in os::pd_pretouch_memory and generate a warning when user turns on UseMadvPopulteWrite when not supported

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/18592/files
  - new: https://git.openjdk.org/jdk/pull/18592/files/fc8abd5c..f5b71360

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18592&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18592&range=00-01

  Stats: 56 lines in 1 file changed: 23 ins; 21 del; 12 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