RFR: 8346460: NotifyFramePop should return JVMTI_ERROR_DUPLICATE

[Serguei Spitsyn]

The JVMTI NotifyFramePop should return JVMTI_ERROR_DUPLICATE in a case the specified FramePop event was already requested. This makes it consistent with the SetBreakpoint which returns the JVMTI_ERROR_DUPLICATE on an attempt to add request a breakpoint that was already requested.

CSR: [8346460](https://bugs.openjdk.org/browse/JDK-8346460): NotifyFramePop should return JVMTI_ERROR_DUPLICATE

Testing:
 - tested with mach5 tiers 1-6

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Commit messages:
 - 8346460: NotifyFramePop should return JVMTI_ERROR_DUPLICATE

Changes: https://git.openjdk.org/jdk/pull/22798/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22798&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8346460
  Stats: 11 lines in 3 files changed: 7 ins; 3 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/22798.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22798/head:pull/22798

PR: https://git.openjdk.org/jdk/pull/22798