[llvm-branch-commits] [BOLT] Require CFG in BAT mode (PR #150488)

[Amir Ayupov via llvm-branch-commits]

https://github.com/aaupov created https://github.com/llvm/llvm-project/pull/150488

`getFallthroughsInTrace` for non-BAT functions requires CFG even for
fdata output only. Since all modes (BAT/non-BAT, YAML/fdata) need CFG:
- drop special BAT/fdata handling in `RewriteInstance::run`,
- in `getFallthroughsInTrace`, directly check if a function has CFG
  constructed => allow non-simple functions.

Test Plan: trace in non-simple function should be accepted