Making the Unicode formatters visually nicer by using the same prefix characters as the compiler expects in C++ code
Also, marking the Unicode data formatters test cases as dataformatter related for the benefit for the --category flag in dotest.py



git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@172167 91177308-0d34-0410-b5e6-96231b3b80d8