Fix test of memory vs. memory converted to registers

The purpose of memtest02 in tests/simple/memory.v is to	test bit
select on both memory (mem1) and memory converted to registers (mem2).

After 7cfae2c52, mem1 was automatically converted to registers,
and the test no longer worked as intended. This is fixed by
adding (* nomem2reg *) to mem1.

tests/simple/memory.v

@@ -44,6 +44,7 @@ input [2:0] bit;
 output reg y1, y2;
 output y3, y4;
 
+(* nomem2reg *)
 reg [7:0] mem1 [3:0];
 
 (* mem2reg *)