ticket:10549: Updates in the performance test case collperf2.

git-svn-id: http://source.icu-project.org/repos/icu/icu/trunk/source@34773 251d0590-4201-4cf1-90de-194747b24ca1
ticket:8464: Make formatting relative dates with quantity more  efficient by preprocessing the pattern strings. Saves 650ns per format.

git-svn-id: http://source.icu-project.org/repos/icu/icu/trunk/source@34784 251d0590-4201-4cf1-90de-194747b24ca1