hush: fix a bunch of obscure while/until/continue bugs

function                                             old     new   delta
run_list                                            1159    1214     +55
done_pipe                                            106     123     +17
done_command                                          86      98     +12
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/0 up/down: 84/0)               Total: 84 bytes

diff --git a/shell/hush_test/hush-misc/until1.tests b/shell/hush_test/hush-misc/until1.tests
new file mode 100644
index 0000000..10ab283
--- /dev/null
+++ b/shell/hush_test/hush-misc/until1.tests
@@ -0,0 +1,11 @@
+x=1
+until test "$x" = 4; do echo $x; x=4; done
+
+# We had a bug in multi-line form
+x=1
+until test "$x" = 4; do
+        echo $x
+        x=4
+done
+
+echo Ok:$?