Remove hex character number from wchar_t test

After r220894 (StringPrinter change) it is no longer emitted. Update the
test rather than considering it a bug as the new format is preferred.


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@220914 91177308-0d34-0410-b5e6-96231b3b80d8