https://bugs.webkit.org/show_bug.cgi?id=83307

Reviewed by Gavin Barraclough.

Replace all usage of static_cast<JSCell subtype*> with jsCast<> in JavaScriptCore.
This results in assertions when unsafe casts are performed, but simply leaves
a static_cast<> in release builds.

* API/APICast.h:
(toJS):
* API/JSCallbackConstructor.cpp:
(JSC::constructJSCallback):
* API/JSCallbackFunction.cpp:
(JSC::JSCallbackFunction::call):
* API/JSCallbackObjectFunctions.h:
(JSC::::asCallbackObject):
(JSC::::finishCreation):
(JSC::::construct):
(JSC::::call):
* API/JSObjectRef.cpp:
(JSObjectGetPrivate):
(JSObjectSetPrivate):
(JSObjectGetPrivateProperty):
(JSObjectSetPrivateProperty):
(JSObjectDeletePrivateProperty):
* API/JSValueRef.cpp:
(JSValueIsObjectOfClass):
* API/JSWeakObjectMapRefPrivate.cpp:
* bytecompiler/BytecodeGenerator.cpp:
(JSC::BytecodeGenerator::resolve):
(JSC::BytecodeGenerator::resolveConstDecl):
* debugger/DebuggerActivation.cpp:
(JSC::DebuggerActivation::finishCreation):
* dfg/DFGOperations.cpp:
* interpreter/Interpreter.cpp:
(JSC::Interpreter::execute):
(JSC::Interpreter::privateExecute):
* jit/JITStubs.cpp:
(JSC::DEFINE_STUB_FUNCTION):
* runtime/Executable.h:
(JSC::isHostFunction):
* runtime/JSActivation.h:
(JSC::asActivation):
* runtime/JSArray.cpp:
(JSC::JSArray::defineOwnProperty):
* runtime/JSArray.h:
(JSC::asArray):
* runtime/JSBoundFunction.cpp:
(JSC::boundFunctionCall):
(JSC::boundFunctionConstruct):
* runtime/JSByteArray.h:
(JSC::asByteArray):
* runtime/JSCell.cpp:
(JSC::JSCell::toObject):
* runtime/JSCell.h:
(JSC::jsCast):
* runtime/JSGlobalObject.h:
(JSC::asGlobalObject):
* runtime/JSGlobalObjectFunctions.cpp:
(JSC::globalFuncEval):
* runtime/JSObject.cpp:
(JSC::JSObject::setPrototypeWithCycleCheck):
(JSC::JSObject::allowsAccessFrom):
(JSC::JSObject::toThisObject):
(JSC::JSObject::unwrappedObject):
* runtime/JSObject.h:
(JSC::asObject):
* runtime/JSPropertyNameIterator.h:
(JSC::Register::propertyNameIterator):
* runtime/JSString.h:
(JSC::asString):
(JSC::JSValue::toString):
* runtime/StringPrototype.cpp:
(JSC::stringProtoFuncSubstr):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@113363 268f45cc-cd09-0410-ab3c-d52691b4dbfc