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/640-always/all.do

@@ -0,0 +1,26 @@
+rm -f always1 always1.log
+
+cd ..
+redo 640-always/always1
+cd 640-always
+[ "$(wc -l <always1.log)" -eq 1 ] || exit 11
+
+# This shouldn't rebuild, but because other people might be running
+# flush-cache in parallel with us, we can't be 100% sure it won't.  So don't
+# test it.
+#redo-ifchange always1
+#[ "$(wc -l <always1.log)" -eq 1 ] || exit 21
+
+../flush-cache
+redo-ifchange always1
+. ../skip-if-minimal-do.sh
+[ "$(wc -l <always1.log)" -eq 2 ] || exit 31
+
+../flush-cache
+redo-ifchange always1
+[ "$(wc -l <always1.log)" -eq 3 ] || exit 41
+
+cd ..
+./flush-cache
+redo-ifchange 640-always/always1
+[ "$(wc -l <640-always/always1.log)" -eq 4 ] || exit 51