[PATCH v5 1/5] jscript: Pass a jsval "this" to builtin functions.

[Jinoh Kang]

Overall, I think there needs to be additional compatibility shim when strict mode is not enabled.

Specifically, if strict mode is disabled for the current execution frame,
it should translate "null" and "undefined" receiver values to the global object of the current realm.

The translation should only need to be done in the call dispatching side though, no need to copy this special case behaviour to every possible callee site.