[llvm] [BOLT][merge-fdata] Fix basic sample profile aggregation without LBR info (PR #118481)

[Paschalis Mpeis via llvm-commits]

https://github.com/paschalis-mpeis commented:

Tests are target-agnostic, right?
If so, could you move them outside of the x86 folder?

Another suggestion would be to minimize the fdata files a bit.
And maybe introducing another fdata file to check that merging lbr/non-lbr profiles is not possible.

Thank you!

https://github.com/llvm/llvm-project/pull/118481