[InstrProf][NFC] Add InstrProfInstBase base

The `InstrProfInstBase` class is for all `llvm.instrprof.*` intrinsics. In a
later diff we will add new instrinsic of this type. Also refactor some
logic in `InstrProfiling.cpp`.

Reviewed By: davidxl

Differential Revision: https://reviews.llvm.org/D117261