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
When a top-level decl is marked with @_originallyDefinedIn, some of its members
may also be newly added after the top-level decl has been moved to the current module.
For these members, we don't need emit $ld$previous$ symbols for them.
rdar://60478650
