Tests to make sure we throw when triggering a custom property with a mismatched this

On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".


PASS testObject.id threw exception TypeError: Type error.
PASS testObject.id="foo" threw exception TypeError: Type error.
PASS testObject.length threw exception TypeError: Type error.
PASS successfullyParsed is true

TEST COMPLETE