RFR: 8315563: Remove references to JDK-8226420 from problem list

Sat Sep 2 00:57:10 UTC 2023

JDK-8226420 has been closed as a duplicate.
The fix removes references to 8226420 from problemlist (the tests remain problem-listed due other issues).

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

Commit messages:
 - Removed 8226420 from problem list

Changes: https://git.openjdk.org/jdk/pull/15548/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15548&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8315563
  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/15548.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15548/head:pull/15548

PR: https://git.openjdk.org/jdk/pull/15548