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/stamp/stamptest.do

@@ -1,72 +0,0 @@
-rm -f stampy usestamp usestamp2 stampy.log usestamp.log usestamp2.log
-echo one >inp
-
-../flush-cache
-redo stampy
-[ "$(wc -l <stampy.log)" -eq 1 ] || exit 11
-
-# stampy already exists, so we won't generate it a second time, even though
-# usestamp depends on it.
-../flush-cache
-redo-ifchange usestamp
-[ "$(wc -l <stampy.log)" -eq 1 ] || exit 21
-[ "$(wc -l <usestamp.log)" -eq 1 ] || exit 12
-
-../flush-cache
-redo stampy
-. ../skip-if-minimal-do.sh
-[ "$(wc -l <stampy.log)" -eq 2 ] || exit 31
-[ "$(wc -l <usestamp.log)" -eq 1 ] || exit 32
-
-# same as above: stampy is already up-to-date, so it won't be redone.
-../flush-cache
-redo-ifchange usestamp
-[ "$(wc -l <stampy.log)" -eq 2 ] || exit 41
-[ "$(wc -l <usestamp.log)" -eq 1 ] || exit 42
-
-# stampy depends on bob, so we'll have to rebuild stampy automatically.  But
-# stampy's checksum will still be identical, so usestamp shouldn't rebuild.
-../flush-cache
-redo bob
-../flush-cache
-redo-ifchange usestamp
-[ "$(wc -l <stampy.log)" -eq 3 ] || exit 43
-[ "$(wc -l <usestamp.log)" -eq 1 ] || exit 44
-
-# Make sure the previous step correctly marked stampy and usestamp as
-# up-to-date even though *neither* of them is newer than bob.
-../flush-cache
-redo-ifchange usestamp
-[ "$(wc -l <stampy.log)" -eq 3 ] || exit 45
-[ "$(wc -l <usestamp.log)" -eq 1 ] || exit 46
-
-# now we're changing the contents of stampy.  Thus usestamp will need to
-# be rebuilt, but not yet...
-echo two >inp
-../flush-cache
-redo stampy
-[ "$(wc -l <stampy.log)" -eq 4 ] || exit 51
-[ "$(wc -l <usestamp.log)" -eq 1 ] || exit 52
-
-# let's see about usestamp.  It needs to be rebuilt because stampy has changed,
-# but since stampy is *already* changed, stampy itself shouldn't be re-rebuilt.
-../flush-cache
-redo-ifchange usestamp usestamp2
-[ "$(wc -l <stampy.log)" -eq 4 ] || exit 61
-[ "$(wc -l <usestamp.log)" -eq 2 ] || exit 62
-[ "$(wc -l <usestamp2.log)" -eq 1 ] || exit 62
-
-# when we delete the file and it gets regenerated identically, it's as good as
-# never having been deleted.  So usestamp won't need to change.
-../flush-cache
-rm -f stampy
-redo-ifchange usestamp usestamp2
-[ "$(wc -l <stampy.log)" -eq 5 ] || exit 71
-[ "$(wc -l <usestamp.log)" -eq 2 ] || exit 72
-[ "$(wc -l <usestamp2.log)" -eq 1 ] || exit 73
-
-# this simple test used to cause a deadlock.
-../flush-cache
-rm -f stampy
-redo-ifchange stampy
-[ "$(wc -l <stampy.log)" -eq 6 ] || exit 74