[llvm] [llvm-profdata] Use simple enum for error checking in Sample Profile Reader (PR #67453)

[David Li via llvm-commits]

https://github.com/david-xl approved this pull request.

ErrorOr/std:error_code are  expensive to construct, so should be limited to error path only. LGTM

https://github.com/llvm/llvm-project/pull/67453