RFR: 8304725: AsyncGetCallTrace can cause SIGBUS on M1 [v6]

[Johannes Bechberger]

> Fixes the issue by disabling PCDesc cache modifications when in ASGCT.
> 
> Tested on my M1 mac.

Johannes Bechberger has updated the pull request incrementally with one additional commit since the last revision:

  Add comments

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Changes:
  - all: https://git.openjdk.org/jdk/pull/13144/files
  - new: https://git.openjdk.org/jdk/pull/13144/files/6f1108ed..5d9df9a6

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13144&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13144&range=04-05

  Stats: 3 lines in 2 files changed: 3 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/13144.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13144/head:pull/13144

PR: https://git.openjdk.org/jdk/pull/13144