https://bugs.webkit.org/show_bug.cgi?id=79170

Reviewed by Sam Weinig.

See ES5.1 8.12.9 10.a.i - the spec prohibits making a read-only property writable,
but does not inhibit making a writable property read-only.

Source/JavaScriptCore: 

* runtime/JSGlobalData.cpp:
(JSC::JSGlobalData::JSGlobalData):
* runtime/JSGlobalData.h:
(JSC::JSGlobalData::setInDefineOwnProperty):
(JSGlobalData):
(JSC::JSGlobalData::isInDefineOwnProperty):
    - Added flag, tracking whether we are in JSObject::defineOwnProperty.
* runtime/JSObject.cpp:
(JSC::JSObject::deleteProperty):
(DefineOwnPropertyScope):
    - Always allow properties to be deleted by DefineOwnProperty - assume it knows what it is doing!
(JSC::DefineOwnPropertyScope::DefineOwnPropertyScope):
(JSC::DefineOwnPropertyScope::~DefineOwnPropertyScope):
    - Added RAII helper.
(JSC::JSObject::defineOwnProperty):
    - Track on the globalData when we are in this method.

LayoutTests: 

* fast/js/Object-defineProperty-expected.txt:
* fast/js/script-tests/Object-defineProperty.js:
    - Update test result (this was enforcing incorrect behaviour).



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@108427 268f45cc-cd09-0410-ab3c-d52691b4dbfc