Decimal -> Decimal cast wrongly fails for large scale reduction

[scovich]

Describe the bug

Today, attempting to converting from e.g. Decimal32(9, 3) to Decimal32(9, -7) fails with an "overflow" error. The overflow in question is computing pow(10, 3 - (-7)) which indeed overflows 32-bit int.

But that overflow is an implementation detail -- the result of the conversion is perfectly well-defined: value/10000000000 rounds to zero, for all possible unscaled decimal32 values.

To Reproduce

Try to convert Decimal32(9, 3) to Decimal32(9, -7)

Expected behavior

The cast should succeed and produce a column of all-zeros values.

Additional context

Discovered by code inspection, as part of reviewing #8552

[alamb]

label_issue.py automatically added labels {'arrow'} from #8580