Fix Swift/Objective-C command line API diffs.
Fix Swift/Objective-C command line API diffs.

e17593e57945010510bf3b3b016df5789dea8cb5 added support for swift package-manager, so we now use the swift package manager to run the tool instead of going through xcode.

material-motion/apidiff,material-motion/apidiff,material-motion/apidiff