RFR: 8265984: Concurrent GC: Some tests fail "assert(is_frame_safe(f)) failed: Frame must be safe"

[Per Liden]

JDK-8265702 introduced a change in `OptoRuntime::handle_exception_C()` where it no longer processed frames when asking for the caller. This change turned out to cause intermittent test failures. We shouldn't have to process frames here, since we're not touching any oops, but it seems that processing frames here avoids some other issue. To avoid noise in out testing I suggest we revert to processing frames here for now (and add the required ThreadWXEnable for macos/aarch64), while we continue to investigate why this is needed.

Testing: Passed tier1-7 on linux/x86 and macos/aarch64

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Commit messages:
 - 8265984: Concurrent GC: Some tests fail "assert(is_frame_safe(f)) failed: Frame must be safe"

Changes: https://git.openjdk.java.net/jdk/pull/3814/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3814&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8265984
  Stats: 5 lines in 2 files changed: 3 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3814.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3814/head:pull/3814

PR: https://git.openjdk.java.net/jdk/pull/3814