[llvm-branch-commits] [CycleInfo] Move scalar cycle accessors to GenericCycleInfo. NFC (PR #209990)

[Fangrui Song via llvm-branch-commits]

https://github.com/MaskRay created https://github.com/llvm/llvm-project/pull/209990

Move getHeader, isReducible, getParentCycle, getDepth, and getNumBlocks
off GenericCycle onto GenericCycleInfo, each taking the cycle by
reference, so callers query a cycle through GenericCycleInfo instead of
calling methods on it. This is a step toward replacing the GenericCycle
pointer with an opaque handle.

Aided by Claude Opus 4.8