[llvm] [nfc] Make function-specialization3.ll test compatible with profile propagation unittests (PR #156942)

[Alan Zhao via llvm-commits]

alanzhao1 wrote:

> change the test to actually have function entry counts (and branch weights)

I'll create a separate PR for that as the original issue (the test failing with profile propagation unittests) is fixed with https://github.com/llvm/llvm-project/pull/156985

https://github.com/llvm/llvm-project/pull/156942