RFR: 8292559: Add test for -XX:+CheckJNICalls showing changed signal handlers [v2]

[Harold Seigel]

> Please review this small change to add a test that option -XX:+CheckJNICalls shows changed signal handlers.  This new test is a copy of the recently deleted TestPosixSig.java with small changes.  This version of the test only checks that handlers were changed for SIGFPE and SIGILL signals.
> 
> The test was tested using Mach5 to run it on Linux, Mac OS, and Windows.
> 
> Thanks, Harold

Harold Seigel has updated the pull request incrementally with one additional commit since the last revision:

  remove ifdef _cplusplus etc.

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/9919/files
  - new: https://git.openjdk.org/jdk/pull/9919/files/0a2e92d5..6bf8fdec

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9919&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9919&range=00-01

  Stats: 11 lines in 1 file changed: 0 ins; 10 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/9919.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9919/head:pull/9919

PR: https://git.openjdk.org/jdk/pull/9919