https://bugs.webkit.org/show_bug.cgi?id=73875

Added 8 bit paths for converions methods.

This is worth 1.5% on kraken audio-oscillator,
1.6% on stanford-crypto-ccm and 2.5% on
stanford-crypto-sha256-iterative.  See bug for
a full report.

Reviewed by Oliver Hunt.

* runtime/JSGlobalObjectFunctions.cpp:
(JSC::decode): Split into a templated helper.
(JSC::parseInt): Split into a templated helper.
(JSC::parseFloat): Added an 8 bit path
(JSC::globalFuncEscape): Added 8 bit path
(JSC::globalFuncUnescape): Added 8 bit path
* runtime/JSStringBuilder.h:
(JSC::JSStringBuilder::append): New append for LChar
* wtf/text/StringBuilder.h:
(WTF::StringBuilder::append): New append for LChar


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@102146 268f45cc-cd09-0410-ab3c-d52691b4dbfc