swift234

[driver] Added serialized diagnostics as an additional output for compile commands.

Added a SerializedDiagnostics entry to Types.def.
In Driver::buildJobsForAction(), set an appropriate path for serialized
diagnostics, if requested. In Swift::constructJob(), check for an additional
SerializedDiagnostics output to determine if -serialize-diagnostics and
-serialized-diagnostics-path should be passed.

This is necessary infrastructure for the output file map.

Swift SVN r12613