swift234

[frontend] Began splitting options in CompilerInvocation into separate classes.

Added a new FrontendOptions class, which will eventually contain the options for controlling the behavior of the frontend. (This is similar to Clang’s FrontendOptions class.)
Moved InputFilenames, OutputFilename, ModuleName, and SerializedDiagnosticsPath from CompilerInvocation into FrontendOptions.
Split out argument parsing for options in FrontendOptions into a separate ParseFrontendArgs static function.

Swift SVN r11155