Cache commonly used classDesc to avoid creating ReferenceClassDescImpl every time
------------- Commit messages: - cache ClassDesc MH/BMH/DMH Changes: https://git.openjdk.org/jdk/pull/21580/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21580&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8342644 Stats: 15 lines in 1 file changed: 12 ins; 0 del; 3 mod Patch: https://git.openjdk.org/jdk/pull/21580.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/21580/head:pull/21580 PR: https://git.openjdk.org/jdk/pull/21580
