* First draft:in js, constructor declaration is preferred
* Add tests
* initializer of null|undefined gives any in JS
Also move this-assignment fixes out of binder. I'm going to put it in
the checker instead.
* In JS, initializer null|undefined: any, []: any[]
* First draft of js prefer-ctor-types overhaul
* Update tests, update baselines
* Improve readability of constructor-type preference
* Cleanup: Remove TODO and duplication
* Add noImplicitAny errors
* Add comment
* Track thisContainer for this-property-assignments in JS
Previously it would update on every block, not just those that could
bind `this`.
In addition, if the constructor symbol still can't be found, then no
binding happens. This is usually OK because people don't add new
properties in methods too often.
* Update additional baselines
* Add lib:dom to new test
* Address PR comments
* Correct new name for saveThisParentContainer
