RFR: 8217383: Obsolete UseImplicitStableValues

[Roman Kennke]

Hi Claes,

The change looks good. Thanks for doing it! I was wondering a couple of
times why this is still in there...

Roman


> Hi,
> 
> the diagnostic flag UseImplicitStableValues has no effect since
> String.value was made explicitly @Stable in JDK 9. This patch obsoletes
> the flag and removes the special-casing of String.value.
> 
> Bug:    https://bugs.openjdk.java.net/browse/JDK-8217383
> Webrev: http://cr.openjdk.java.net/~redestad/8217383/open.00/
> 
> Testing: tier1-3, verified no regressions in a few String
> microbenchmarks
> 
> CSR filed and approved.
> 
> Thanks!
> 
> /Claes