fix interface conversion erroneously renaming colliding pattern names

test/basic/interface_struct_label.sv

@@ -0,0 +1,18 @@
+interface Interface;
+    logic x;
+endinterface
+
+module Module (
+    Interface p
+);
+    typedef struct packed {
+        integer p;
+    } S;
+    S s = '{ p: 1 };
+    initial $display("%0d %0d", s, s.p);
+endmodule
+
+module top;
+    Interface intf();
+    Module mod(intf);
+endmodule

test/basic/interface_struct_label.v

@@ -0,0 +1,3 @@
+module top;
+    initial $display("%0d %0d", 1, 1);
+endmodule