Text('f'): 0 x 100 = 000

When multiplying 0 with some number, the resulting Text('f') shows too many zeroes. I expect the result to return "0"

```
x := new(apd.Decimal)
_, _ = x.SetFloat64(0)

multiplier := new(apd.Decimal)
_, _ = multiplier.SetFloat64(100)

result := new(apd.Decimal)
_, _ = apd.BaseContext.Mul(result, x, multiplier)

fmt.Println(result.Text('f')) // 000
```