RFR: Fix store check

[Aleksey Shipilev]

On 10/28/2016 09:24 PM, Roman Kennke wrote:
> There were two mistakes in the store check assembly:
> - It was comparing against first_region_bottom instead of
> last_region_end
> - It was using a 32-bit immediate compare op. For 64 bit, the operand
> needs to be copied into a tmp register first, and then compare against
> that.
> 
> http://cr.openjdk.java.net/~rkennke/fixstorecheck/webrev.00/

OK.

-Aleksey