[CMake] add_llvm_library: Specify explicit suffix .imp to import library to avoid a warning between profile_rt-static and profile_rt-shared with lib/profile_rt.lib.
[CMake] add_llvm_library: Specify explicit suffix .imp to import library to avoid a warning between profile_rt-static and profile_rt-shared with lib/profile_rt.lib.

FIXME: It seems MS version of profile_rt.dll doesn't contain any export symbols.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@188351 91177308-0d34-0410-b5e6-96231b3b80d8

chubbymaggie/asap,llvm-mirror/llvm,llvm-mirror/llvm,dslab-epfl/asap,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,chubbymaggie/asap,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,chubbymaggie/asap,llvm-mirror/llvm,dslab-epfl/asap,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,chubbymaggie/asap,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,dslab-epfl/asap,llvm-mirror/llvm,dslab-epfl/asap,GPUOpen-Drivers/llvm,apple/swift-llvm,dslab-epfl/asap,chubbymaggie/asap,chubbymaggie/asap,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,dslab-epfl/asap,dslab-epfl/asap