RFR: Add read barriers to C1's vectorizedMismatch() intrinsic

[Aleksey Shipilev]

On 09/21/2016 01:16 PM, Roman Kennke wrote:
> http://cr.openjdk.java.net/~rkennke/c1_vect_mismatch/webrev.00/

Looks good to me.

I don't think we have to create folders for each test in
test/gc/shenandoah for these one-off failures, TBH. But no matter, we
can always rearrange later.

Thanks,
-Aleksey