[CMake] Fix standalone build after LLVM exports utility targets
[CMake] Fix standalone build after LLVM exports utility targets

LLVM started exporting targets for utilites with https://reviews.llvm.org/rL350959, which broke compiler-rt standalone builds because it was used to define FileCheck manually.
Changed this, so FileCheck gets imported now.

git-svn-id: c199f293c43da69278bea8e88f92242bf3aa95f7@350973 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