RFR: 8221836: Avoid recalculating String.hash when zero

[Claes Redestad]

On 2019-04-09 15:03, Andrew Dinn wrote:
>> How about this:
>> http://cr.openjdk.java.net/~redestad/8221836/open.03/
> Yes, that looks fine.

Thanks, Andrew. I'll push this shortly.

/Claes