Merge branch 'kk/tests-with-no-perl'

Some tests were not skipped under NO_PERL build.

* kk/tests-with-no-perl:
  reset test: modernize style
  t/t7106-reset-unborn-branch.sh: Add PERL prerequisite
  add -i test: use skip_all instead of repeated PERL prerequisite
  Make test "using invalid commit with -C" more strict