additional interface conversion test coverage

test/basic/interface_unbound.v

@@ -0,0 +1,15 @@
+module Module(x);
+    input wire x;
+    initial $display("Hello!");
+    initial #1 $display(x);
+endmodule
+
+module top;
+    generate
+        if (1) begin
+            wire x;
+            Module m1(x);
+            Module m2(x);
+        end
+    endgenerate
+endmodule