[llvm] [nfc][InstrProfTest]Factor out common code for value profile test (PR #72611)

[Mingming Liu via llvm-commits]

minglotus-6 wrote:

> Are these changes inter-dependent or can be further split into smaller NFC patches?

This could be further split. Keep the refactor of three related tests in this PR, and going to use separate PRs for the rest.

https://github.com/llvm/llvm-project/pull/72611