Fix bugs in unit_tree "-/*" rule.

Address review comments from previous cl.
Remove unneeded unit_tree filter from cast and flutter.
Fix 4 cases of dropping of [ls][dgs] in zone_tree.

Data Size   ICU63    ICU64    DIFF
chromeos  10326064 10378624   52560
  common  10326064 10394816   68752
    cast   5126144  5101616  -24528
 android   6355520  6406256   50736
     ios   6315248  6372016   56768
 flutter    880928   894752   13824

We also save 43K in
https://chromium-review.googlesource.com/c/v8/v8/+/1478710

Bug: chromium:943348
Change-Id: Ibd7f2a09e07db017dec30fbaaef7e11d593e5a3b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/deps/icu/+/1552147
Reviewed-by: Jungshik Shin <jshin@chromium.org>
13 files changed