CLDR time zone names in "en" bundle are expected to be pre-populated for
performance. This is not the case for locales that have "en-001" (World
English) as the parent bundle, such as Locale.CANADA. The fast path
determining logic was incorrectly assumed all English locales are using
pre-populated bundles. Limiting the assumption to only "en" and "en-US"
will solve the problem.