[compiler] PruneNonEscapingScopes understands terminal operands#33062

Stack from [ghstack](https://github.com/ezyang/ghstack) (oldest at bottom): * __->__ #33062 Handles a few edge cases relating to for..of terminals, which have a compound `init` value block: * For..of with a return statement inside would not memoize the rvalue of the init expression (the collection). This is because there was no direct dependency relationship between the value being returned and the outer scope. The fix is to track the set of active scopes and make return values depend on all the active scopes at the point of the return. * For..of that reassigns a variable which later escapes were also not memoizing the collection. This is similar: the escape analysis aliasing didn't consider scopes that reassign, so there was no dependency between the returned variable and the scope that did the reassigning. The fix is to establish that dependency relationship. In both cases, adding the additional scopes as a dependency of the right variable ensures that the scope's dependencies are treated as escaping (needing memoization), ensuring the collection is memoized.