RFR: 8229283: StringLatin1 should consistently use CharacterDataLatin1.instance when applicable

[Claes Redestad]

Hi,

in j.l.StringLatin1 we can and do call CharacterDataLatin1 directly in
some places, which avoids a few indirections. Doing so has no effect on 
peak performance, but simplifies the work the JIT needs to do and speeds
up a variety of operations during startup and warmup.

http://cr.openjdk.java.net/~redestad/8229283/open.00/
https://bugs.openjdk.java.net/browse/JDK-8229283

Pre-existing StringUpperLower microbenchmark sees 1.5-1.9x
improvements when run with -Xint or -XX:TieredStopAtLevel=1. Affected
operations are very common, so there are tiny but measurable gains
across a diverse set of startup tests.

Thanks!

/Claes