[Object] Add tapi files to object

Summary:
The intention for this is to allow reading and printing symbols out from
llvm-nm. Tapi file, and Tapi universal follow a similiar format to
their respective MachO Object format.

The tests are dependent on llvm-nm processing tbd files which is why its in D66160

Reviewers: ributzka, steven_wu, lhames

Reviewed By: ributzka, lhames

Subscribers: mgorny, hiraditya, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66159

llvm-svn: 369600