Clang enforces a minimum 13.1 deployment target. The driver, API
checker, and various tests assume 13.0 is a valid minimum. Update these
to reflect the actual 13.1 minimum.
Resolves rdar://84177900
Short overview of new TBD-v4 format changes:
* special section for reexported symbols (which is not seen any
differently to the linker)
* target based slices as opposed to just architecture
more information in: rdar://problem/60586390