Don't add HintedType instances to UnsureType if the target type exists
But only do this if the HintedType also has the same context, otherwise
they might be invalidated at separate times and removing one of them
removes the still valid other HintedType.
If we don't deduplicate here we still get UnsureTypes which have lots
of entries like this:
found potential duplicates when adding N6Python10HintedTypeE int(index = 774764) ->
67278 - int of type N8KDevelop13StructureTypeE 102814 (aka 67278: int of type N8KDevelop13StructureTypeE) - int of type N6Python10HintedTypeE 139700 (aka 67278: int of type N8KDevelop13StructureTypeE) - int of type N6Python10HintedTypeE 140778 (aka 67278: int of type N8KDevelop13StructureTypeE) - int of type N6Python10HintedTypeE 191576 (aka 67278: int of type N8KDevelop13StructureTypeE) - int of type N6Python10HintedTypeE 206348 (aka 67278: int of type N8KDevelop13StructureTypeE) - int of type N6Python10HintedTypeE 346692 (aka 67278: int of type N8KDevelop13StructureTypeE) - int of type N6Python10HintedTypeE 351636 (aka 67278: int of type N8KDevelop13StructureTypeE) - int of type N6Python10HintedTypeE 362174 (aka 351724: int of type N6Python10UnsureTypeE) - int of type N6Python10HintedTypeE 386886 (aka 67278: int of type N8KDevelop13StructureTypeE) - int of type N6Python10HintedTypeE 408898 (aka 67278: int of type N8KDevelop13StructureTypeE) - int of type N6Python10HintedTypeE 533652 (aka 67278: int of type N8KDevelop13StructureTypeE) - int of type N6Python10HintedTypeE 540306 (aka 67278: int of type N8KDevelop13StructureTypeE) - int of type N6Python10HintedTypeE 573586 (aka 67278: int of type N8KDevelop13StructureTypeE) - int of type N6Python10HintedTypeE 614644 (aka 67278: int of type N8KDevelop13StructureTypeE) - int of type N6Python10HintedTypeE 618548 (aka 66042: bool of type N8KDevelop12IntegralTypeE) - bool of type N6Python10HintedTypeE 648374 (aka 67278: int of type N8KDevelop13StructureTypeE) - int of type N6Python10HintedTypeE 665250 (aka 67278: int of type N8KDevelop13StructureTypeE) - int of type N6Python10HintedTypeE 709684 (aka 67278: int of type N8KDevelop13StructureTypeE) - int of type N6Python10HintedTypeE 750432 (aka 67278: int of type N8KDevelop13StructureTypeE) - int of type N6Python10HintedTypeE 89504 (aka 66548: str of type N8KDevelop13StructureTypeE) - str of type N6Python10HintedTypeE 765024 (aka 90024: str of type N6Python10UnsureTypeE) - str of type N6Python10HintedTypeE 774764 (aka 403436: int of type N6Python10UnsureTypeE) - int of type N6Python10HintedTypeE
REVIEW: 127039
CCBUG: 358563