RFR(XS): 7035177: G1: nsk/stress/jni/jnistress002 fails with an assertion failure caused by changes for 7009266

[John Cuthbertson]

Hi Everyone,

Can I have a couple of volunteers to look over the fix for this CR? The 
webrev can be found at: http://cr.openjdk.java.net/~johnc/7035177/webrev.0/.

The problem is that the node representing the offset (in an 
Unsafe.getObject compilation) could be typed as a long and generating 
the compare of offset against java_lang_ref_Reference::referent_offset 
(typed as an int) caused an assertion failure about the mis-matching types.

The fix is to generate a suitably typed constant based upon the type of 
"offset".

Tested using the failing test case from the nightly tests.

Thanks,

JohnC