RFR: 8254566: Clarify the spec of ClassLoader::getClassLoadingLock for non-parallel capable loader

[Mandy Chung]

8254566: Clarify the spec of ClassLoader::getClassLoadingLock for non-parallel capable loader

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

Commit messages:
 - 8254566: Clarify the spec of ClassLoader::loadClass about the lock acquired by non-parallel capable loader

Changes: https://git.openjdk.org/jdk/pull/14720/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14720&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8254566
  Stats: 12 lines in 1 file changed: 6 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/14720.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14720/head:pull/14720

PR: https://git.openjdk.org/jdk/pull/14720