allow packages to reference their own items explicitly

test/error/package_self_reference_loop.sv

@@ -0,0 +1,8 @@
+// pattern: package "P" references undeclared local "P::Foo"
+package P;
+    localparam Foo = P::Foo;
+endpackage
+module top;
+    import P::*;
+    initial $display(Foo);
+endmodule