SI-7519 Less brutal attribute resetting in adapt fallback

Prefers `resetLocalAttrs` over `resetAllAttrs`. The latter loses
track of which enclosing class of the given name is referenced by
a `This` node which prefixes the an applied implicit view.

The code that `resetAllAttrs` originally landed in: https://github.com/scala/scala/commit/d4c63b#L6R804

Review by @xeno-by. Let's run it by @odersky, too.

I wonder: when would a `resetAllAttrs` *ever* be appropriate?