RFR: 8314247: JVMCI: expected int64_t but JavaThread::_held_monitor_count is of type intx

[Coleen Phillimore]

Fix graal error with @iklam's fix of making intx and int64_t synonyms.  Tested with new test in jvmci tests.

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Commit messages:
 - 8314247: JVMCI: expected int64_t but JavaThread::_held_monitor_count is of type intx

Changes: https://git.openjdk.org/jdk/pull/15295/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15295&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8314247
  Stats: 13 lines in 2 files changed: 10 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/15295.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15295/head:pull/15295

PR: https://git.openjdk.org/jdk/pull/15295