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: a4a6f32337ebd29ad4763b423022f00f68d1c7b7@125174 91177308-0d34-0410-b5e6-96231b3b80d8

lodyagin/bare_cxx,lodyagin/bare_cxx,lodyagin/bare_cxx,lodyagin/bare_cxx,lodyagin/bare_cxx