Update ASTRONOMICAL_UNIT definition to IAU 2012 standard

[yososs]

The current implementation of ASTRONOMICAL_UNIT in the CLDR module uses an outdated astronomical value.

Current Implementation:

public static final Unit<Length> ASTRONOMICAL_UNIT = addUnit(METRE.multiply(149597870691.0));

The value 149,597,870,691.0 reflects an older observational estimate (likely around IAU 2009).

Standard Definition (IAU 2012):
According to the International Astronomical Union (IAU) 2012 Resolution B2, the astronomical unit is redefined as a conventional unit of length and is exactly 149,597,870,700 metres.

Expected Behavior

The value should be updated to match the current international standard:
METRE.multiply(149597870700.0)

Actual Behavior

The current value differs by approximately 9 meters from the official IAU definition, which may lead to inconsistencies in high-precision astronomical calculations.

Reference

• Wikipedia: Astronomical unit