Swift: restrict UnresolvedAstNodes to known locations

swift/ql/consistency-queries/UnresolvedAstNodes.ql

@@ -1,5 +1,8 @@
 import swift
 
-from AstNode n
-where n.getAPrimaryQlClass().matches("Unresolved%")
-select n
+from AstNode n, string cls
+where
+  cls = n.getAPrimaryQlClass() and
+  cls.matches("Unresolved%") and
+  not n.getLocation() instanceof UnknownLocation
+select n, cls