RFR: 8300644: Remove gc/shenandoah/jni/TestStringCriticalWithDedup.java [v2]

[Erik Österlund]

> The gc/shenandoah/jni/TestStringCriticalWithDedup.java test was designed to catch failure to pin strings being passed out to JNI critical users, because that used to be dangerous. After [JDK-8299673](https://bugs.openjdk.org/browse/JDK-8299673) that is not dangerous any longer. Conversely, now we kind of want deduplication to proceed regardless of JNI critical, which defeats the purpose of this test. It should be removed.

Erik Österlund has updated the pull request incrementally with one additional commit since the last revision:

  Remove unused file

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Changes:
  - all: https://git.openjdk.org/jdk/pull/12089/files
  - new: https://git.openjdk.org/jdk/pull/12089/files/ca12e310..ef92536b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12089&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12089&range=00-01

  Stats: 39 lines in 1 file changed: 0 ins; 39 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/12089.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12089/head:pull/12089

PR: https://git.openjdk.org/jdk/pull/12089