RFR: 8291569: Consider removing JNI checks for signals SIGPIPE and SIGXFSZ [v2]

[David Holmes]

> Simple enhancement to skip checking of the handlers for SIGPIPE and SIGXFSZ as we really don't care if they change, and we expect that they can.
> 
> The signal checking code might seem to have a redundancy as we skip these signals in two places, but the primary use of the `do_check_signal_periodically` array is to allow for only issuing one warning per signal. I could have skipped them in either place and get the same effect but it seemed inappropriate to set the array entry and not do the check; and vice-versa.
> 
> Testing: just basic sanity test tiers 1-3. This doesn't affect any application behaviour.
> 
> There are no regression tests in this specific area and it did not seem worth the effort creating one just for this.
> 
> Thanks.

David Holmes has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:

 - Merge branch 'master' into 8291569-signals
 - 8291569: Consider removing JNI checks for signals SIGPIPE and SIGXFSZ

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/12062/files
  - new: https://git.openjdk.org/jdk/pull/12062/files/b5442e7d..1a6ac606

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12062&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12062&range=00-01

  Stats: 12251 lines in 535 files changed: 6663 ins; 1265 del; 4323 mod
  Patch: https://git.openjdk.org/jdk/pull/12062.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12062/head:pull/12062

PR: https://git.openjdk.org/jdk/pull/12062