RFR: 8344199: Incorrect excluded field value set by getEventWriter intrinsic

[Tobias Hartmann]

The C2 intrinsic for `jdk.jfr.internal.JVM::getEventWriter` sets a boolean `excluded` field by masking the most significant bit of the unsigned 2-byte `thread_epoch_raw` field value. A shift is needed to get a proper boolean value.

Thanks,
Tobias

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Commit messages:
 - 8344199: Incorrect excluded field value set by getEventWriter intrinsic

Changes: https://git.openjdk.org/jdk/pull/22195/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22195&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8344199
  Stats: 11 lines in 2 files changed: 6 ins; 1 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/22195.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22195/head:pull/22195

PR: https://git.openjdk.org/jdk/pull/22195