Array extractors can collide with assignments

[JLHwung]

They are already valid JS:

// variable declaration + assignment
let Foo
(x) = y

// assignment + assignment
Foo
(x.z) = y

Here are some solutions for this issue:

1. forbid the line terminator between QualifiedName[?Yield, ?Await] and ExtractorArrayBindingPattern[?Yield, ?Await]
2. use other sigils for the array pattern, i.e. ||, ~[], etc.
3. innovate the syntax, i.e. let [x] with Foo = y, etc.

[JLHwung]

Sorry for the noise. I actually turned on error recovery mode and overlook the errors.