HourCyclesOfLocale: Add language subtag to lookup

[anba]

HourCyclesOfLocale performs a lookup based only on the region subtag, but CLDR's Time Data accepts locale identifiers in addition to standalone region subtags.

For example new Intl.Locale("en-CA").getHourCycles()[0] should return "h12", whereas new Intl.Locale("fr-CA").getHourCycles()[0] should return "h23", but the current spec text doesn't allow this result.

[ptomato]

The lookup using locale identifiers already seems to be web reality. JSC and V8 are the only engines implementing getHourCycles so far, and they both return h23 for fr-CA. (I haven't yet looked at the code to see if they actually do the lookup with locale identifiers.)

However, based on what I see in CLDR 48 they should be returning ['h23', 'h12'] whereas they are actually returning only ['h23']. I guess it depends on what your definition of "in common use" is.