Avoid building CreateTimeZoneDistro for target

CreateTimeZoneDistro is not needed on target but it's
included with TimeZoneDistroBuilder, which is used in
target tests. This commit splits the host-only tool build
target from the "just the builder" target.

Bug: 119806864
Test: build
Test: Run update-tzdata.py (which calls create-distro.py)
Change-Id: I7684b1b29edb996306597db85bcc6d2a7ee62638
6 files changed