literal methods; add EnvrionmentRecord fields and methods to
LexicalEnvironment
Adding EnvrionmentRecord's fields and methods lets us throw an exception
when |this| is not initialized, which occurs when the super constructor
in a derived class has not yet been called, or when |this| has already
been initialized (the super constructor was already called).
This rewrite drastically increases the accuracy of object literals.
Additionally, an "assertIsSyntaxError" function has been added to
test-common.js to assist in testing syntax errors.
The addition of assert functions to Userland/js
was done before we had load(..) implemented. Now
that it exists, it seems like the right move the
test helper functions to pure javascript instead
of poluting js with random global functions.
The PropertyName class able to match a number or an array can only
accept positive numerical values. However, the computed_property_name
method sometimes returned negative values.
This commit also adds a basic object access test case.
