hush testsuite: add many tests from ash testsuite

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/shell/hush_test/hush-signals/signal6.right b/shell/hush_test/hush-signals/signal6.right
new file mode 100644
index 0000000..df4d930
--- /dev/null
+++ b/shell/hush_test/hush-signals/signal6.right
@@ -0,0 +1,2 @@
+got TERM
+Done: 0