ticket:10070: uregion_isEqualTo -> uregion_areEqual, implement using pointer compare

git-svn-id: http://source.icu-project.org/repos/icu/icu@33578 251d0590-4201-4cf1-90de-194747b24ca1
ticket:10128: minor updates to sync with ICU4J

git-svn-id: http://source.icu-project.org/repos/icu/icu@33580 251d0590-4201-4cf1-90de-194747b24ca1
ticket:10128: remove incorrect comment

git-svn-id: http://source.icu-project.org/repos/icu/icu@33582 251d0590-4201-4cf1-90de-194747b24ca1