RFR: 6536943: Bogus -Xcheck:jni warning for SIG_INT action for SIGINT in JVM started from non-interactive shell

[Yumin Qi]

Hi, Can I have your codereview for this simple change:

http://cr.openjdk.java.net/~minqi/6536943/webrev00/

Summary: Under non-interactive shell,  -Xcheck:jni output warning for 
SIGINT, since non-interactive shells set SIGINT to SIG_IGN as part of 
the job control features. The fix is that don't check signal handlers if 
java run in a non-interactive shell. This applies to all  platforms 
except for Windows.

Thanks
Yumin