Unit test for upward path search without LHS (#2087)

Author: ike709

Content.Tests/DMProject/Tests/Tree/upward_search_path3.dm

@@ -0,0 +1,8 @@
+
+//# issue 617
+
+/datum/foo
+/datum/bar/var/meep = .foo
+/proc/RunTest()
+    var/datum/bar/D = new
+    ASSERT(D.meep == /datum/foo)