[RuntimeAsync] Revisit TODOs in places of questionable intersections of existing scenarios and Async

[VSadov]

We have a number of scenarios that may or may not be reachable with Async methods, but right now do not have a well defined behavior if Async methods get there. A good example is COM interop.
Such scenarios are stubbed to throw exceptions and marked with // TODO: (async) revisit and examine if this needs to be supported

Some of these places may be truly unreachable, some may need to be made unreachable and in some cases we may need to provide some kind of support for Async.

This is the tracking issue to make sure that all these TODOs are revisited and removed after providing appropriate behavior.

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