Update tests to use test-chmtime

test-lib:
  Make sure test-chmtime has been built before starting.

t4200-rerere:
  Removed non-portable date dependency and avoid touch
  Avoid "test -a" which isn't portable, either

lib-git-svn:
  Use test-chmtime instead of Perl one-liner to poke

Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Junio C Hamano <junkio@cox.net>

t/lib-git-svn.sh

@@ -46,5 +46,5 @@ rawsvnrepo="$svnrepo"
 svnrepo="file://$svnrepo"
 
 poke() {
-	perl -e '@x = stat($ARGV[0]); utime($x[8], $x[9] + 1, $ARGV[0])' "$1"
+	test-chmtime +1 "$1"
 }