Daylight Savings Time Optimization Followups

[nik9000]

After we merge #55559 we'll have a few things to clean up:

• Implement interval rounding (Speed up time interval arounding around dst #56371)
• Cache LocalTimeOffset.Lookups to avoid building them over and over again. They are quite expensive to build and would likely cache very well.
• Investigate how expensive loading the min and max is. Maybe we can cache them on the reader or something.
• Plug this in to auto_date_histogram. It could speed it up a ton. (Speed up rounding in auto_date_histogram #56384)
• Remove the optimization that rewrites non-fixed time zones into fixed ones in date_histogram. It won't really do anything after we get interval rounding. (Drop rewriting in date_histogram #57836)
• Speed up nextRoundingValue to make date histogram on date ranges faster.

Maybe:

• Plug this in to composite. It might not benefit much from it but then again it might. It is worth checking.

[elasticmachine]

Pinging @elastic/es-analytics-geo (:Analytics/Aggregations)

[nik9000]

* Cache `LocalTimeOffset.Lookup`s to avoid building them over and over again. They are quite expensive to build and would likely cache very well.

The kind of cache that we'd need to build makes this maybe not something we should do. We'd get terrible hit rate if we just used the range and zone id as the key and java.util.time isn't that slow to give us the data that we need. I'll think about this one some more.