ticket:9648: Changed BasicTimeZone public API methods to const.

git-svn-id: http://source.icu-project.org/repos/icu/icu/trunk/source@33109 251d0590-4201-4cf1-90de-194747b24ca1
ticket:9839: Removed temporary workaround in the test code.

git-svn-id: http://source.icu-project.org/repos/icu/icu/trunk/source@33110 251d0590-4201-4cf1-90de-194747b24ca1