[jdk20u] RFR: 8306883: Thread stacksize is reported with wrong units in os::create_thread logging

[Thomas Stuefe]

I'd like to backport this trivial change to fix the broken thread attach logging that confuses analysts with the wrong thread stack size.

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Commit messages:
 - Backport 27c5c1070ac559caa8dbad598337046f59355464

Changes: https://git.openjdk.org/jdk20u/pull/66/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk20u&pr=66&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8306883
  Stats: 7 lines in 4 files changed: 0 ins; 0 del; 7 mod
  Patch: https://git.openjdk.org/jdk20u/pull/66.diff
  Fetch: git fetch https://git.openjdk.org/jdk20u.git pull/66/head:pull/66

PR: https://git.openjdk.org/jdk20u/pull/66