[BasicAA] Don't pass through AA metadata (NFCI)

BasicAA itself doesn't make use of AA metadata, but passes it
through to recursive queries and makes it part of the cache key.
Aliasing decisions that are based on AA metadata (i.e. TBAA and
ScopedAA) are based *only* on AA metadata, so checking them with
different pointer values or sizes is not useful, the result will
always be the same.

While this change is a mild compile-time improvement by itself,
the actual goal here is to reduce the size of AA cache keys in
a followup change.

Differential Revision: https://reviews.llvm.org/D90098