Consider removing JNI checks for signals SIGPIPE and SIGXFSZ

If -XX:+CheckJNICall is specified then the JVM checks (see os::run_peridoc_checks) if its signal handlers have been overridden for multiple signals, including SIGPIPE and SIGXFSZ. Since the JVM ignores SIGPIPE or SIGXFSZ the checks for these signals can possibly be removed.

The signals are currently ignored by this code in signals_posix.cpp:

  // Ignore SIGPIPE and SIGXFSZ (4229104, 6499219).
  if (!signal_was_handled &&
      (sig == SIGPIPE || sig == SIGXFSZ)) {
    PosixSignals::chained_handler(sig, info, ucVoid);
    signal_was_handled = true; // unconditionally.
  }