This is equivalent to the existing `scaleLargeTimestamp` method with the
following changes/improvements:
* No longer specific to timestamps (there was nothing inherently
time-specific about the logic in `scaleLargeTimestamp`, but the name
and docs suggested it shouldn't be used for non-timestamp use-cases).
* Additional 'perfect division' checks between `value` and `divisor`.
* The caller can now provide a `RoundingMode`.
* Robust against `multiplier == 0`.
* Some extra branches before falling through to (potentially lossy)
floating-point math, including trying to simplify the fraction with
greatest common divisor to reduce the chance of overflowing `long`.
This was discussed during review of 6e91f0d4c5
This change also includes some golden test file updates - these
represent a bug fix where floating-point maths had previously resulted
in a timestamp being incorrectly rounded down to the previous
microsecond. These changes are due to the 'some more branches' mentioned
above.
PiperOrigin-RevId: 564760748
885ddb167e