ash: add most of hush process subst tests

ash passes these.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/shell/ash_test/ash-psubst/tick4.right b/shell/ash_test/ash-psubst/tick4.right
new file mode 100644
index 0000000..d8030ea
--- /dev/null
+++ b/shell/ash_test/ash-psubst/tick4.right
@@ -0,0 +1,7 @@
+(TEST) BEST
+TEST) BEST
+((TEST) BEST
+)
+abc
+a)c
+OK: 0