[llvm] [NFC][LLVM] Namespace cleanup in AddressSanitizer.cpp (PR #163776)

[Thurston Dang via llvm-commits]

https://github.com/thurstond requested changes to this pull request.

Title is misleading: this pull request also changes llvm/lib/Transforms/Instrumentation/ControlHeightReduction.cpp
(or is that a stray change?)

https://github.com/llvm/llvm-project/pull/163776