PERF: use (UTF-8) optimized String/CS encoding path
PERF: use (UTF-8) optimized String/CS encoding path

a very noticeable performance improvement on String/CS encoding
since JRuby is able to utilize its "fast" UTF-8 encoding paths

- we also re-invented `RubyString.newInternalFromJavaExternal`
... this is likely going to get back-ported to **JRuby 9.2.1**

jruby/activerecord-jdbc-adapter,jruby/activerecord-jdbc-adapter,kares/activerecord-jdbc-adapter,kares/activerecord-jdbc-adapter,kares/activerecord-jdbc-adapter,bruceadams/activerecord-jdbc-adapter,jruby/activerecord-jdbc-adapter,bruceadams/activerecord-jdbc-adapter,bruceadams/activerecord-jdbc-adapter