RFR: 8215547: ZGC: Fix incorrect match rule for loadBarrierWeakSlowRegNoVec

[Per Liden]

Nils, Erik and I discussed this further off-line and found a few other 
inconsistencies and potential bugs. Here's an updated webrev reflecting 
that:

http://cr.openjdk.java.net/~pliden/8215547/webrev.1

This patch has passed tier1-6 and 10+ iterations in gc-test-suite.

/Per

On 12/18/18 10:45 AM, Per Liden wrote:
> The AD matching for loadBarrierWeakSlowRegNoVec is incorrect. It should 
> match against a LoadBarrierWeakSlowReg, not LoadBarrierSlowReg.
> 
> Also the format lines for loadBarrier*SlowRegXmmAndYmm are missing the 
> "AndYmm" part.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8215547
> Webrev: http://cr.openjdk.java.net/~pliden/8215547/webrev.0
> 
> /Per