Rename tests from <foo> to <foo>_test to match the FreeBSD test suite naming scheme usr.bin/diff/diff_test was renamed to usr.bin/diff/netbsd_diff_test to avoid collisions with the renamed FreeBSD test.
Rename tests from <foo> to <foo>_test to match the FreeBSD test suite naming scheme usr.bin/diff/diff_test was renamed to usr.bin/diff/netbsd_diff_test to avoid collisions with the renamed FreeBSD test.