RFR(S) 8185134: Introduce vm.graal predicate

[Doug Simon]

Looks good to me.

> On 20 Sep 2017, at 07:04, Ekaterina Pavlova <ekaterina.pavlova at oracle.com> wrote:
> 
> Hi all,
> 
> could you please review this small change which introduces vm.graal.enabled predicate
> and marks compiler tests which fail with Graal due to c2 specific checks by '@requires !vm.graal.enabled'.
> 
>    bug: https://bugs.openjdk.java.net/browse/JDK-8185134
> webrev: http://cr.openjdk.java.net/~epavlova//8185134_test/
>         http://cr.openjdk.java.net/~epavlova//8185134_hs/
> 
> 
> Tested by running failing tests in Graal as JIT compiler mode
> (-XX:+TieredCompilation -XX:+UseJVMCICompiler -Djvmci.Compiler=graal).
> 
> thanks,
> -katya
> 
> p.s.
> Igor Ignatyev volunteered to sponsor this change.