[llvm-branch-commits] [BOLT] Cover all call sites in writeBATYAML (PR #87743)

[Amir Ayupov via llvm-branch-commits]

https://github.com/aaupov created https://github.com/llvm/llvm-project/pull/87743

Combine blocks from cold fragments in getBFBranches.

Depends on https://github.com/llvm/llvm-project/pull/87569

Test Plan: Updated bolt/test/X86/yaml-secondary-entry-discriminator.s