LLVM's lit implementation switched to use process pools in r299775.
This exposed some pickling problems in Swift's lit files. For a function
or class to be pickle-able, it has to be in the top-level of a real
Python module.
* The SwiftTest lit format class was embedded in the lit.cfg file, so
I moved it out to a separate Python file.
* The inferSwiftBinary function was being stashed in the
config.inferSwiftBinary field and later used to find tools for SourceKit
testing. I moved the config settings for those tools into the top-level
lit.cfg file. I expect this will cause warnings about them not existing
in some cases, but that should be fairly harmless. Maybe someone can
come up with a better solution later.
* The config.substitutions for SourceKit's lit.local.cfg was storing a
reference to an embedded sed_clean function, which just returned a
constant string. I changed the function to be a string, using Python's
raw string feature to avoid the problems that likely led to it being a
function in the first place. (Just guessing.)
