JIT + INTERPRETER builds are broken

Reviewed by Geoff Garen, Sam Weinig.

These don't fallback to the interpreter correctly.
Thunk creation assumes that is the JIT is compiled in, then it is enabled.

* jit/JITStubs.cpp:
(JSC::JITThunks::JITThunks):
* runtime/Executable.h:
(JSC::NativeExecutable::create):
(JSC::NativeExecutable::finishCreation):
* runtime/JSGlobalData.cpp:
(JSC::JSGlobalData::getHostFunction):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@102011 268f45cc-cd09-0410-ab3c-d52691b4dbfc