lit/Util.py: Add two functions, checkToolsPath(dir,tools) and whichTools(tools,paths).
lit/Util.py: Add two functions, checkToolsPath(dir,tools) and whichTools(tools,paths).

checkToolsPath(dir,tools):
return True if "dir" contains all "tools".

whichTools(tools,paths):
return a directory that contains all "tools" in "paths".
Or return None when all "tools" were not met.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@125174 91177308-0d34-0410-b5e6-96231b3b80d8

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