Re-format destructuring assignment tests

Utilize the test generation tool to increase coverage of destructuring
assignment semantics. Previously, only destructuring assignment in the
AssignmentExpression position was tested. With this change applied, the
same tests will assert expected behavior for destructuring assignment in
`for..of` statements, as well.

A limited number of tests are applied to the `for..in` statement as
well, but due to the iteration protocol observed by that statement, many
destructuring tests are not relevant, and others cannot be automatically
generated from this format.