[10] Review Request: 8187442 Xcheck:jni produces various "WARNING in native method" in launcher

[Sergey Bylokhov]

Hello,
Please review the fix for jdk10/jdk10.

Bug: https://bugs.openjdk.java.net/browse/JDK-8187442
Webrev can be found at: http://cr.openjdk.java.net/~serb/8187442/webrev.00

The simple application with empty main method produce some "warnings" 
when Xcheck:jni is used. Because of that it is hard to cleanup other 
parts of jdk from such warnings.

Two additional checks were added, in both cases the new code will return 
0 in the same way as NULL_CHECK0 in the same methods.


-- 
Best regards, Sergey.