tzdata & zoneinfo version test

This test verifies that

• the drop-in Time Zone .res files used by icu::TimeZone, and
• the zoneinfo tzif2 files used by absl::TimeZone and cctz

are kept in sync to the same upstream revision. This ensures that components that rely on the Fuchsia platform to provide time zone data will see a consistent set of time zone definitions, regardless of which of the two libraries they use.

Building and Tesing

fx set core.x64 --with //src/tests/intl/tzdata
# ... start fx serve and fx emu
fx test //src/tests/intl/tzdata