Fix CMake warning in CFI tests.
Fix CMake warning in CFI tests.

CFI tests do not require the CFI runtime library on Windows.
Do not add "cfi" as a dependency of "check-cfi" in that case.

git-svn-id: c199f293c43da69278bea8e88f92242bf3aa95f7@257202 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt