Tests: Add case for `bind` into parametrised hier_block

Using `bind` into a parametrized hier_block used to be broken due to name
mangling, but was 'unintentionally' fixed by
916a89761e. Adding test to avoid
regressions.

test_regress/t/t_hier_block.v

@@ -268,6 +268,8 @@ module sub4 #(
       end
    end
 
+   int driven_from_bind = 0;
+
    always @(posedge clk) begin
       count <= count + 1;
       if (count > 0) begin
@@ -284,6 +286,11 @@ module sub4 #(
                 end
             end
          end
+
+         if (driven_from_bind != int'(2*P1)) begin
+           $display("%m driven_from_bind: %0d != %0d", driven_from_bind, int'(2*P1));
+           $stop;
+         end
       end
    end
 endmodule
@@ -361,3 +368,14 @@ module delay #(
       assign out = tmp;
    end
 endmodule
+
+// Module bound into parametrized hier_block that undergoes name mangling
+module sub4_bound #(
+  parameter P1 = 1
+) (
+  output int driven_from_bind
+);
+  assign driven_from_bind = int'(P1*2);
+endmodule
+
+bind sub4 sub4_bound #(.P1(P1)) i_sub4_bound (.*);