Revert "Implement equality semantics for async tagger tags."

[genlu]

Reverts #64802 to fix errors in insertion, which breaks TypeScript tagger

1. Implement equality semantics for async tagger tags. #64802 (comment)
2. https://github.com/dotnet/roslyn/pull/64802/files#r1000998300

FYI @CyrusNajmabadi a dual insertion with TS is required to reinstate the change

[CyrusNajmabadi]

what is the error in insertion?

[CyrusNajmabadi]

if there is a third party that is extending this type, we can solve this by making the member non-abstract, and giving it a default impl of object.Equals(tag1, tag2);

[CyrusNajmabadi]

I can make such a change fyi.

[CyrusNajmabadi]

Non-breaking fix here: #64869

[RikkiGibson]

In general, it's encouraged to link the associated insertion when opening a revert.

[genlu]

@RikkiGibson Thanks for the reminder, link to insertion added

[Cosifne]

BTW the original change also breaks the Integration test.
See my PR here for the fix #64852