RFR: 8284828: Use `os::ThreadCrashProtection` to protect AsyncGetCallTrace from crashing [v4]

[Johannes Bechberger]

> Move the AsyncGetCallTrace method implementation into a separate method and wrap its call in non-assert compilation mode in `os::ThreadCrashProtection` like it is done in [JFR](https://github.com/openjdk/jdk/blob/965ea8d9cd29aee41ba2b1b0b0c67bb67eca22dd/src/hotspot/share/jfr/periodic/sampling/jfrThreadSampler.cpp#L165).
> This prevents AsyncGetCallTrace from crashing on segmentation faults (but not on `guarantee`s).
> 
> If a crash is observed, then the `num_frames` field of the trace is set to `ticks_unknown_state` (-7) to signal a state that cannot be properly handled. `ticks_unknown_state` is currently also used for signaling unknown thread states but this should not be a problem, as the semantic is the same. If `num_frames` already has an error code then this error code is not changed. This helps to distinguish between errors in walking threads in Java and non-Java mode, as `num_frames` is set there before the walking to the appropriate error code.
> 
> _Thanks for @tstuefe for suggesting this._

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

  Remove JFR assert from ThreadCrashProtection
  
  Remove the Thread::is_JfrSampler_thread() method too,
  as it has only be used by the removed asserts

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8225/files
  - new: https://git.openjdk.java.net/jdk/pull/8225/files/d3a66505..77a21cb5

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8225&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8225&range=02-03

  Stats: 9 lines in 6 files changed: 1 ins; 4 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8225.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8225/head:pull/8225

PR: https://git.openjdk.java.net/jdk/pull/8225