ticket:9101: RBC has-an immutable, ref-counted CollationTailoring, does not depend on builder; CollationTailoring*Data*Builder

git-svn-id: http://source.icu-project.org/repos/icu/icu/branches/markus@33429 251d0590-4201-4cf1-90de-194747b24ca1
ticket:9101: some root elements checks, builder.hasMappings()

git-svn-id: http://source.icu-project.org/repos/icu/icu/branches/markus@33432 251d0590-4201-4cf1-90de-194747b24ca1