UTF conversion routines were moved from clang/Basic to llvm/Support


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@173935 91177308-0d34-0410-b5e6-96231b3b80d8
llvm/Basic/ConvertUTF.h now exposes all functions without macro tricks


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@173937 91177308-0d34-0410-b5e6-96231b3b80d8