The "Tool" abstraction wasn't buying us enough to deserve the added
complexity. Now a ToolChain turns Actions into Jobs, and every helper
tool is searched for relative to Swift first. Much simpler.
Swift SVN r31563
Most of the tests just got moved to swiftc, but some of them were
duplicated to apply to both swiftc and swift. A handful still use the
existing 'swift' because they are for the existing '-i' syntax.
Note: this means config.swift_driver now uses the staging symlink
'swifti'. The only thing preventing us from dropping the 'i' and getting
rid of the old interface is that Xcode hasn't moved to swiftc yet
<rdar://problem/17769327>.
Swift SVN r20467
First, use -driver-print-output-file-map to ensure that the map we write out is, in fact, being deserialized properly.
Then, use -driver-print-bindings to ensure that we are preferring values in the output file map to default output paths.
Swift SVN r12775
