[jdk21u-dev] RFR: 8335237: ubsan: vtableStubs.hpp is_vtable_stub exclude from ubsan checks

[Matthias Baesken]

Backport of 8335237, diff in stride at headers

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

Commit messages:
 - Backport 486aa11e74d0772ba84c2adc3c62fc1fcbf52604

Changes: https://git.openjdk.org/jdk21u-dev/pull/899/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=899&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8335237
  Stats: 5 lines in 1 file changed: 4 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/899.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/899/head:pull/899

PR: https://git.openjdk.org/jdk21u-dev/pull/899