[llvm][llvm-nm] add TextAPI/MachO support
This completes the needed glueing to support reading tbd files from nm.
This includes specifying which slice filtering with --arch and a new
option specifically for tbd files --add-inlinedinfo which will show
the reexported libraries that are appended in the tbd file.
Reviewers: ributzka, steven_wu, JDevlieghere, jhenderson
Reviewed By: JDevlieghere
Subscribers: hiraditya, MaskRay, dexonsmith, rupprecht, llvm-commits
Differential Revision: https://reviews.llvm.org/D81614