[llvm-branch-commits] [BOLT][NFCI] Skip validation in parseLBRSample (PR #143288)

[Amir Ayupov via llvm-branch-commits]

https://github.com/aaupov created https://github.com/llvm/llvm-project/pull/143288

Parsed branches and fall-throughs are validated in `doBranch` and
`doTrace` respectively. Simplify parseLBRSample by omitting the
validation. This also speeds up perf data processing as checks are only
done once for aggregated branches/fall-throughs and not individual LBR
entries.

Test Plan: NFC