BytecodeGenerator needs to be re-entrant to support miranda functions

BytecodeGenerator needs to be re-entrant to support miranda functions
https://bugs.webkit.org/show_bug.cgi?id=142627

Reviewed by Filip Pizlo.

Made CodeCache::getGlobalCodeBlock and CodeCache::getFunctionExecutableFromGlobalCode re-entrant
by not keeping AddResult while invoking BytecodeGenerator::generate.

This is needed to support Miranda functions since they need to be lazily initialized.

* runtime/CodeCache.cpp:
(JSC::CodeCache::getGlobalCodeBlock):
(JSC::CodeCache::getFunctionExecutableFromGlobalCode):
* runtime/CodeCache.h:
(JSC::CodeCacheMap::findCacheAndUpdateAge): Extracted from add.
(JSC::CodeCacheMap::addCache): Extracted from add.
(JSC::CodeCacheMap::add): Deleted.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@181482 268f45cc-cd09-0410-ab3c-d52691b4dbfc