JNI ReleasePrimitiveArrayCritical with mode JNI_COMMIT shouldn't end critical region

[Ian Rogers]

From:
https://docs.oracle.com/javase/8/docs/technotes/guides/jni/spec/functions.html#GetPrimitiveArrayCritical_ReleasePrimitiveArrayCritical

"The semantics of these two functions are very similar to the existing
Get/Release<primitivetype>ArrayElements functions. "

https://docs.oracle.com/javase/8/docs/technotes/guides/jni/spec/functions.html#Release_PrimitiveType_ArrayElements_routines

"JNI_COMMIT copy back the content but do not free the elems buffer"

Consider the pattern of:
GetPrimitiveArrayCritical(...)
ReleasePrimitiveArrayCritical(..., JNI_COMMIT)
ReleasePrimitiveArrayCritical(..., 0)

where the first release is to just achieve a copy back. For example,
jniCheck.cpp will copy back but not free a copy in the case of JNI_COMMIT
for a critical. The implementation of ReleasePrimitiveArrayCritical ignores
all arguments and so it ends the critical region even in the event of a
commit.

The attached patch makes ReleasePrimitiveArrayCritical consider the mode
argument when releasing the GCLocker.

Thanks,
Ian
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