RFR: 8233019: java.lang.Class.isPrimitive() (C1) returns wrong result if Klass* is aligned to 32bit

[Yangfei (Felix)]

Hi,

I see 8u backport for JDK-8150669 has been approved for [1]. 
Before pushing 8u backport for [1], I would like to get another reviewing for 8u fix for [2]. 
This resolves the corner case that leads to incorrect result for C1 intrinsic, so I think it will be safer to push these two fixes together to 8u. 

Original patch for 11u: https://hg.openjdk.java.net/jdk-updates/jdk11u-dev/rev/e1b6631cbd2f 
Patch does not apply cleanly to 8u: arm and s390 ports are not there and we don’t have c1 compiler support in ppc port in 8u. 

8u-backport patch based on [3]:
https://cr.openjdk.java.net/~dongbohe/8233019-8u/8233019-8u.diff 

Performed full jtreg test both on x86_64-linux-gnu and aarch64-linux-gnu platforms. 

Thanks,
Felix

[1] https://bugs.openjdk.java.net/browse/JDK-8150669 
[2] https://bugs.openjdk.java.net/browse/JDK-8233019 
[3] http://cr.openjdk.java.net/~fyang/8150669-8u/webrev.00