Sometimes we only want to ensure that we can produce snippets (all the way
through `SnippetRepetitor`!), but don't care for the execution.
E.g. all of our tests are this way.
I've built LLVM without PFM and removed my CPU from `X86PfmCounters.td`,
and this produces the expected results in that configuration.
Reviewed By: courbet
Differential Revision: https://reviews.llvm.org/D139448
7a76140220
