[llvm-branch-commits] [BOLT] Drop perf2bolt cold samples diagnostic (PR #139337)

[Amir Ayupov via llvm-branch-commits]

https://github.com/aaupov created https://github.com/llvm/llvm-project/pull/139337

Cold samples diagnostics in perf2bolt are superseded by
`print-heatmap-stats` option. It provides a superset of stats and works
without BAT section (not emitted by default).

Test Plan: NFC