[jdk18] RFR: 8280155: [PPC64, s390] frame size checks are not yet correct

[Martin Doerr]

Fix frame size check and do null check earlier as described in the JBS issue.

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

Commit messages:
 - Update Copyright years.
 - [PPC64, s390] frame size checks are not yet correct

Changes: https://git.openjdk.java.net/jdk18/pull/107/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk18&pr=107&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8280155
  Stats: 11 lines in 3 files changed: 4 ins; 1 del; 6 mod
  Patch: https://git.openjdk.java.net/jdk18/pull/107.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk18 pull/107/head:pull/107

PR: https://git.openjdk.java.net/jdk18/pull/107