[analyzer] Refactor makeNull to makeNullWithWidth (NFC)

[analyzer] Refactor makeNull to makeNullWithWidth (NFC)

Usages of makeNull need to be deprecated in favor of makeNullWithWidth
for architectures where the pointer size should not be assumed. This can
occur when pointer sizes can be of different sizes, depending on address
space for example. See https://reviews.llvm.org/D118050 as an example.

This was uncovered initially in a downstream compiler project, and
tested through those systems tests.

steakhal performed systems testing across a large set of open source
projects.

Co-authored-by: steakhal
Resolves: https://github.com/llvm/llvm-project/issues/53664

Reviewed By: NoQ, steakhal

Differential Revision: https://reviews.llvm.org/D119601