Improve multiplication in vm

This patch improves the ecma_integers_values multiplication by checking if the multiplier or multiplicand is power of 2.
If it is it uses right shift instead of multiplication.

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik frobert@inf.u-szeged.hu

jerry-core/vm/vm.c

@@ -1793,7 +1793,7 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
                 && left_value != 0
                 && right_value != 0)
             {
-              result = ecma_make_integer_value (left_integer * right_integer);
+              result = ecma_integer_multiply (left_integer, right_integer);
               break;
             }