Fixes #17097
Fixes #17070
Fixes #16777

This change makes relating the following types faster:

interface B<T> {
  contents: T[]
  map<U>(f: (t: T) => U): B<U>
}
interface D<T> extends B<T> {
  contents: List<T>
  map<U>(f: (t: T) => U): D<U>
}

Previously, relating the return types of map, D<U> ===> B<U>, would cause a recursive check. This recursion would continue until the depth limit was hit. However, no new information will result from relating D<U> ===> B<U> vs D<T> ===> B<T> — one type parameter is interchangeable with any other in terms of relatability (with the exception of constrained type parameters).

With this change, the check in recursiveTypeRelatedTo for whether a type is already being compared will treat A<T> not by its identity but the identity of A and its type arguments. Previously, A<T> and A<U> would have different ids. Now, they both have ids like "111=0", if A.id = 111. Because both T and U are unconstrained type parameters, they just get a simple index based on when they were first seen in the argument list. A type like C<T, number, number, U, T> would produce a key like 112=0-33-33=1=0 where C.id=112 and number.id=33.

Like #17947, this changes fixes immview and Immutable.js's oomemory crashes from 2.4.1. And it finishes about 10% faster. It also fixes the ng-typeview and monet crashes provided in #16777.

I tested the performance of this change and #17947. On TFS and Monaco, there is no performance difference with either change. I also ran the change on our real-world code corpus. Some duplicate error elaborations disappear from identical errors because of improved caching (in linq, RxJs, etc), but this is a slight improvement overall.