[llvm] [NFC][Support] Add an include file for time profiler helpers for tools (PR #152416)

[Min-Yih Hsu via llvm-commits]

https://github.com/mshockwave commented:

Personally I prefer:
  1. Put the RAII class in `llvm/Support/TimeProfiler.h`
  2. Define command line options in `lib/Support/TimeProfile.cpp`, and _maybe_ provide getter functions for options that user might want to access (e.g. `time-trace-file`)

For the RAII class, you could provide a variety of ctors so that users can either choose to supply their time trace file path / granularity or using the ones given by the command line options.

https://github.com/llvm/llvm-project/pull/152416