RFR: 8344525: Fix leftover ExceptionOccurred in java.base

[Justin Lu]

Please review this PR which removes the leftover ocurrences of incorrect JNI `ExceptionOccurred(env)` usage within _java.base_. 

This PR also includes 9 cases of `if (ExceptionOccurred(env) == NULL)`. While these occurrences are fine and were intentionally not removed during the first pass, it would be consistent with the other related JNI ExceptionOccurred cleanups to include them here as well. Making the swap also avoids creating the `jthrowable` reference in the first place (even if automatically freed later).

After this patch, the remaining instances of `ExceptionOccurred(env)` within _j.base_ are used with intent to create the `jthrowable` reference.

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Commit messages:
 - init

Changes: https://git.openjdk.org/jdk/pull/22266/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22266&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8344525
  Stats: 16 lines in 6 files changed: 0 ins; 0 del; 16 mod
  Patch: https://git.openjdk.org/jdk/pull/22266.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22266/head:pull/22266

PR: https://git.openjdk.org/jdk/pull/22266