ticket:9101: add setMaxVariable() & getMaxVariable(), deprecate setVariableTop()

git-svn-id: http://source.icu-project.org/repos/icu/icu@34772 251d0590-4201-4cf1-90de-194747b24ca1
ticket:10549: Updates in the performance test case collperf2.

git-svn-id: http://source.icu-project.org/repos/icu/icu@34773 251d0590-4201-4cf1-90de-194747b24ca1