msh: create testsuite (based on hush one)

hush: add TODO (doesn't know ":" command)

shell/msh_test/msh-parsing/quote3.tests

@@ -0,0 +1,8 @@
+if test $# = 0; then
+    exec "$THIS_SH" quote3.tests abc "d e"
+fi
+
+echo 'Testing: in $empty""'
+empty=''
+for a in $empty""; do echo ".$a."; done
+echo Finished