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

[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

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Commit messages:
 - 8292559: Add test for -XX:+CheckJNICalls showing changed signal handlers

Changes: https://git.openjdk.org/jdk/pull/9919/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9919&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8292559
  Stats: 124 lines in 3 files changed: 123 ins; 0 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