Various tests, particularly the client program tests under src/bin, use the Perl TAP tools and are run using the Perl testing program prove. You can pass command-line options to prove by setting the make variable PROVE_FLAGS, for example:
make -C src/bin check PROVE_FLAGS='--timer'
See the manual page of prove for more information.
The TAP tests require the Perl module IPC::Run. This module is available from CPAN or an operating system package. They also require PostgreSQL to be configured with the option --enable-tap-tests.