Perform gc-state checks with LoadB to fit C2 matchers

[Aleksey Shipilev]

On 06/12/2018 06:29 PM, Roman Kennke wrote:
>> [1] https://bugs.openjdk.java.net/browse/JDK-8204479
> 
> Patch is ok.
> 
> Why don't we have matchers for LoadUB anymore?

Because C2 is wonderful, see the bug report above.

-Aleksey