[jdk17u-dev] RFR: 8313782: Add user-facing warning if THPs are enabled but cannot be used

[Christoph Langer]

Hi all,

This pull request contains a backport of [JDK-8313782](https://bugs.openjdk.org/browse/JDK-8313782), commit [44b5b81f](https://github.com/openjdk/jdk21u/commit/44b5b81f76567d0b7fc4687e18c53d7ddbd2e982) from the [openjdk/jdk21u](https://git.openjdk.org/jdk21u) repository.

Thanks!

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Commit messages:
 - Backport 44b5b81f76567d0b7fc4687e18c53d7ddbd2e982

Changes: https://git.openjdk.org/jdk17u-dev/pull/1978/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1978&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8313782
  Stats: 13 lines in 1 file changed: 5 ins; 3 del; 5 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1978.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/1978/head:pull/1978

PR: https://git.openjdk.org/jdk17u-dev/pull/1978