t/*: rearrange tests into numbered directories.

It was getting way too ad-hoc in there.  Let's reorganize the tests so that
there's a good, obvious, suggested sequence to run them in.

t/100-args/passfailtest.do

@@ -0,0 +1,15 @@
+. ../skip-if-minimal-do.sh
+
+rm -f pleasefail
+redo passfail
+[ -e passfail ] || exit 42
+PF1=$(cat passfail)
+touch pleasefail
+redo passfail 2>/dev/null && exit 43
+[ -e passfail ] || exit 44
+PF2=$(cat passfail)
+[ "$PF1" = "$PF2" ] || exit 45
+rm -f pleasefail
+redo passfail || exit 46
+PF3=$(cat passfail)
+[ "$PF1" != "$PF3" ] || exit 47