[AliasAnalysis] Misc fixes for checking aliasing with scalable types.

This is fixing up various places that use the implicit
TypeSize->uint64_t conversion.

The new overloads in MemoryLocation.h are already used in various places
that construct a MemoryLocation from a TypeSize, including MemorySSA.
(They were using the implicit conversion before.)

Differential Revision: https://reviews.llvm.org/D76249