RFR: 8345422: Fix JNI Checker "in native method" warnings in the debug agent and debugger tests [v2]

[Chris Plummer]

> The root cause of [JDK-8344804](https://bugs.openjdk.org/browse/JDK-8344804) seems to be some JNI Checker warnings. I decided to resolve all the warnings in the debug agent and debugger tests that start with "in native method". This seems to have resolved [JDK-8344804](https://bugs.openjdk.org/browse/JDK-8344804) failure. There are still other JNI Checker warnings present that are not being dealt with at this time.
> 
> Testing:
> - [x] All tier1
> - [x] All tier2 svc tests
> - [x] All tier3 svc tests
> - [x] All tier4, which is where [JDK-8344804](https://bugs.openjdk.org/browse/JDK-8344804) reproduced
> - [x] All tier5 svc tests

Chris Plummer has updated the pull request incrementally with one additional commit since the last revision:

  use saveGlobalRefHelper() for invokeNonvirtual()

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/22528/files
  - new: https://git.openjdk.org/jdk/pull/22528/files/c4e5ffd1..3d524c85

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22528&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22528&range=00-01

  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/22528.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22528/head:pull/22528

PR: https://git.openjdk.org/jdk/pull/22528