Implement assignment to undefined reference in ES5 Strict Mode.

Implement assignment to undefined reference in ES5 Strict Mode.

Strict mode assignment to undefined reference.
Simple assignments (x = <value>) use CODE_TARGET_CONTEXT.
StoreIC stores its own strictness in extra_ic_state.
The strcitness is propagated as further ic stubs are generated.

Details:
* ReferenceError on assignment to non-resolvable reference in strict mode.
* Fix es5conform test expectation file.
* Add es5conform test suite into .gitignore.
* Fix Xcode project.
* Change implemented in virtual frame code generator, as well as full-codegen
  for all architectures.
* Fix debugger test.
* Fix comment for CODE_TARGET_CONTEXT
* Implement remaining StoreIC stubs to be strict mode aware.
* Trace extra_ic_state() for ic code stubs.

Code Review URL: http://codereview.chromium.org/6474026/

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6756 ce2b1a6d-e550-0410-aec6-3dcde31c8c00