ticket:9101: fix reset twice before root CE; adjust special reset positions according to previous rules

git-svn-id: http://source.icu-project.org/repos/icu/icu/branches/markus@33942 251d0590-4201-4cf1-90de-194747b24ca1
ticket:9101: further adjust first-xyz positions to weaker-before nodes

git-svn-id: http://source.icu-project.org/repos/icu/icu/branches/markus@33943 251d0590-4201-4cf1-90de-194747b24ca1
ticket:9101: use first real CEs for first-variable/regular/trailing, not boundary CEs; fix tailoring to trailing primaries

git-svn-id: http://source.icu-project.org/repos/icu/icu/branches/markus@33949 251d0590-4201-4cf1-90de-194747b24ca1