Ensure parse error on property assignment with string property name and no initializer

[dsherret]

For exmaple, doing the following in the REPL:

> [{"a"}];
Uncaught SyntaxError: Unexpected token '<'

This doesn't seem to make sense, but swc parses this fine by default and transforms it to:

[
    {
        "a": <invalid>
    }
];

We should inspect parser.take_errors() to see if there is a diagnostic here that we could surface as a parse error. I will do this after #11581 lands (don't want to bother with conflicts).