Build: Drop missing checkstyle suppressions (#34490)

This drops checkstyle suppressions that refer to files that don't exist
since those suppressions don't do anything other than make us feel bad.

It also updates some suppressions to more closely match the path to the
file that they suppress. These suppressions are still needed but didn't
pass the "the file exists" test because they weren't precise. It is just
easier on future-me if they are precise.

Author: nik9000