[jdk21u-dev] RFR: 8312136: Modify runtime/ErrorHandling/TestDwarf.java to split dwarf and decoder testing

[Goetz Lindenmaier]

I backport this for parity with 21.0.3-oracle.

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Commit messages:
 - Backport e2e8e8e210ea9a7a9d901a1da729551714015d04

Changes: https://git.openjdk.org/jdk21u-dev/pull/185/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=185&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8312136
  Stats: 37 lines in 2 files changed: 30 ins; 0 del; 7 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/185.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/185/head:pull/185

PR: https://git.openjdk.org/jdk21u-dev/pull/185