https://bugs.webkit.org/show_bug.cgi?id=113086

Reviewed by Geoffrey Garen.

opaqueJSClassData stores cached prototypes for JSClassRefs in the C API. It doesn't make sense to 
share these prototypes within a JSGlobalData across JSGlobalObjects, and in fact doing so will cause 
a leak of the original JSGlobalObject that these prototypes were created in. Therefore we should move 
this cache to JSGlobalObject where it belongs and where it won't cause memory leaks.

* API/JSBase.cpp: Needed to add an extern "C" so that testapi.c can use the super secret GC function.
* API/JSClassRef.cpp: We now grab the cached context data from the global object rather than the global data.
(OpaqueJSClass::contextData):
* API/JSClassRef.h: Remove this header because it's unnecessary and causes circular dependencies.
* API/tests/testapi.c: Added a new test that makes sure that using the same JSClassRef in two different contexts
doesn't cause leaks of the original global object.
(leakFinalize):
(nestedAllocateObject): This is a hack to bypass the conservative scan of the GC, which was unnecessarily marking
objects and keeping them alive, ruining the test result.
(testLeakingPrototypesAcrossContexts):
(main):
* API/tests/testapi.mm: extern "C" this so we can continue using it here.
* runtime/JSGlobalData.cpp: Remove JSClassRef related stuff.
(JSC::JSGlobalData::~JSGlobalData):
* runtime/JSGlobalData.h:
(JSGlobalData):
* runtime/JSGlobalObject.h: Add the stuff that JSGlobalData had. We add it to JSGlobalObjectRareData so that 
clients who don't use the C API don't have to pay the memory cost of this extra HashMap.
(JSGlobalObject):
(JSGlobalObjectRareData):
(JSC::JSGlobalObject::opaqueJSClassData):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@146682 268f45cc-cd09-0410-ab3c-d52691b4dbfc