RFR: 8265292: [macos_aarch64] java/foreign/TestDowncall.java crashes with SIGBUS

[Anton Kozlov]

Please review a fix for the intermittent crash. It is caused by a mistake in the ProgrammableInvoker::invoke_native, the wrong order of W^X and JavaThread state transition. We need WXExec since we are about to call a generated stub. But we need to switch to WXExec only after JavaThread state change. The thread state change may trigger a safepoint, that would need to do bookkeeping in the codecache (MarkActivationClosure::do_code_blob from the bug). So the fix is to change JavaThread state first, then change WX.

The fix was verified with the help of https://bugs.openjdk.java.net/browse/JDK-8266742. The new check catches all test failures reported by 8265292, 8265183, 8265182. I've verified tests pass after the fix with that new check enabled.

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Commit messages:
 - Fix java/foreign SIGBUS on macos/aarch64

Changes: https://git.openjdk.java.net/jdk/pull/3921/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3921&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8265292
  Stats: 5 lines in 2 files changed: 1 ins; 4 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3921.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3921/head:pull/3921

PR: https://git.openjdk.java.net/jdk/pull/3921