RFR: (8030875) Macros for checking and returning on exceptions

[roger riggs]

Please review:

To enable native code checking consistently for thrown exceptions,
the macros in net_util.h and java/util/jar/pack/coding.cpp are
made consolidated and promoted to jni_util.h

webrev:
http://cr.openjdk.java.net/~rriggs/webrev-check-exception-8030875/

[1] https://bugs.openjdk.java.net/browse/JDK-8030875