Revert: ResolveOverloaded should handle alternatives that are the same TermRef
Revert: ResolveOverloaded should handle alternatives that are the same TermRef

This happens once we do not merge methods with the same signature coming
from the same class. (reverted from commit 83262d090a98e2374c9b3e5a1480892397d695d3)

This case no longer applies as such a situation will now give a MergeError instead.

dotty-staging/dotty,som-snytt/dotty,dotty-staging/dotty,som-snytt/dotty,lampepfl/dotty,som-snytt/dotty,dotty-staging/dotty,lampepfl/dotty,sjrd/dotty,sjrd/dotty,sjrd/dotty,dotty-staging/dotty,lampepfl/dotty,som-snytt/dotty,lampepfl/dotty,sjrd/dotty,lampepfl/dotty,sjrd/dotty,som-snytt/dotty,dotty-staging/dotty