Is there a way to create an infinite Decimal?

In Decimal implementation I can see that `isInfinite`

is always false:

```
/// `true` iff `self` is infinity.
public var isInfinite: Bool { return false }
```

What I tried is:

```
Decimal(Double.infinity)
```

but it will "freeze" an execution, probably because of a while loop inside the `init`

function:

```
while Double(UInt64.max - 1) < val {
val /= 10.0
exponent += 1
}
```