[llvm] Group the InstrumentationTests target with other LLVM unit test targe… (PR #170041)

[Pavel Samolysov via llvm-commits]

samolisov wrote:

@LegalizeAdulthood Sorry. I'm not sure I'm a right person for the review, I do not use Visual Studio or any other IDE this CMake configuration makes sense for. Anyway, I'm not sure the instrumentation is for LLM only. May be this is a typo and should be `LLVM`?

https://github.com/llvm/llvm-project/pull/170041