Merge branch 'jc/diff-test-updates' into maint

Test clean-up. * jc/diff-test-updates: test_ln_s_add: refresh stat info of fake symbolic links t4008: modernise style t/diff-lib: check exact object names in compare_diff_raw tests: do not borrow from COPYING and README from the real source t4010: correct expected object names t9300: correct expected object names t4008: correct stale comments