RFR: JDK-8290901: Reduce use of -source in langtools tests

Sat Jul 23 02:35:48 UTC 2022

To a first approximation, this change replaces use of "-source", where possible, with the preferable "--release" javac option. (There are cases where this swap is not desirable, such as when newer library features are being used in the test.)

A few unneeded uses of -source were removed entirely.

I'll update copyrights before any push.

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

Commit messages:
 - JDK-8290901: Reduce use of -source in langtools tests

Changes: https://git.openjdk.org/jdk/pull/9622/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9622&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8290901
  Stats: 116 lines in 81 files changed: 0 ins; 20 del; 96 mod
  Patch: https://git.openjdk.org/jdk/pull/9622.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9622/head:pull/9622

PR: https://git.openjdk.org/jdk/pull/9622