Previously, some of the zones were only removed from the zones
map, not the map of links. Upstream tzdata added a link involving
HST in commit a0b09c0230089252acf2eb0f1ba922e99f7f4a03
("Mark CET, CST6CDT etc. as obsolescent").
During file output, fail with an error if a region cannot be
found, instead of creating a corrupt file.
The zone removal code in the javazic compiler is different.
It handles only GMT-related zones and already applies the
removal (actually, skipping during parsing) to both Zone
and Link records.
Resolves: RHEL-59542
