InstrProf: Test for appropriate linkage of the profiling structures
InstrProf: Test for appropriate linkage of the profiling structures

This test checks that the symbols instrprof creates have appropriate
linkage. The tests already exist in clang in a slightly different form
from before we sunk profile generation into an LLVM pass, but that's
an awkward place for them now. I'll remove/simplify the clang versions
shortly.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@230383 91177308-0d34-0410-b5e6-96231b3b80d8

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