ticket:8176: Moved uses of UVector to UVector32 where possible.

git-svn-id: http://source.icu-project.org/repos/icu/icu/branches/tkeep@33343 251d0590-4201-4cf1-90de-194747b24ca1
ticket:9914: Merge r33243 to r33343 from trunk.

git-svn-id: http://source.icu-project.org/repos/icu/icu/branches/tkeep@33344 251d0590-4201-4cf1-90de-194747b24ca1