Add checkinput build target

This would allow us to check large refactorings without having to
remember individual pieces of code in various places. All of the
input-related code can now be built with a single command.

Bug: 198472780
Test: m checkinput
Change-Id: I2b54d6bc7c08b2cbf2dcb504cfe11d5986d4afc6
1 file changed