ticket:10458: Accedpt \uxxxx and \Uxxxxxxxx in fields that take uchar32 or unicodestring. In errors, print non-printable chars in \uxxxx notation.

git-svn-id: http://source.icu-project.org/repos/icu/icu@36705 251d0590-4201-4cf1-90de-194747b24ca1
ticket:10458: Clear accumulator with each new test header insted of with each verifyPattern statement.

git-svn-id: http://source.icu-project.org/repos/icu/icu@36706 251d0590-4201-4cf1-90de-194747b24ca1