[8u] [JFR] RFR: 8236160: Missing ThreadCrashProtection for JFR in signal handler

[Denghui Dong]

Hi all,
  Please help review the following changeset:
Jira: https://bugs.openjdk.java.net/browse/JDK-8236160
Webrev: http://cr.openjdk.java.net/~ddong/8236160/webrev.00/hotspot.changeset
Summary:
JFR thread sampler uses ThreadCrashProtection to protect thread crash, so it's necessary to call
ThreadCrashProtection::check_crash_protection in signal handler.
And a more elegant way is to merge ThreadCrashProtection and WatcherThreadCrashProtection, but this changeset didn't do that.

Thanks,
Denghui Dong