[TextAPI] Introduce TBDv4

Summary:
This format introduces new features and platforms
The motivation for this format is to support more than 1 platform since previous versions only supported additional architectures and 1 platform,
for example ios + ios-simulator and macCatalyst.

Reviewers: ributzka, steven_wu

Reviewed By: ributzka

Subscribers: mgorny, hiraditya, mgrang, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67529

llvm-svn: 374058