RFR: C2: Clean up load barrier stub generator

[Stefan Karlsson]

Looks good.

StefanK

On 2018-03-14 09:23, Per Liden wrote:
> Adding some comments and cleaning up C2's load barrier slow path stub.
> 
> http://cr.openjdk.java.net/~pliden/zgc/stub_cleanup/webrev.0/
> 
> /Per