[flang-commits] [flang] [flang][NFC] Restrict -funroll-loops tests to known working targets (PR #123939)

[Tom Eccles via flang-commits]

tblah wrote:

@mustartt did you intend the issue to be for the failing tests or that the flag does not produce the intended result on powerpc?

https://github.com/llvm/llvm-project/pull/123939