fix sizeof(array + integer)

Previously sizeof would return the size of the array although the
expression is always a plain pointer of 4 (or 8) bytes.

tccgen.c

@@ -1306,6 +1306,7 @@ void gen_op(int op)
                 swap(&t1, &t2);
             }
             type1 = vtop[-1].type;
+            type1.t &= ~VT_ARRAY;
 #ifdef TCC_TARGET_X86_64
             vpushll(pointed_size(&vtop[-1].type));
 #else