[lldb] Fix initialization order warnings.

Moved the declaration of m_kind below the declaration of cvclass,
cvunion and cvenum. This order is necessary because in one of the
constructors the initialization of m_kind depends on the value of
cvclass.

third_party/llvm/llvm/tools/lldb/source/Plugins/SymbolFile/NativePDB/PdbUtil.cpp:50:7: error: field 'cvclass' will be initialized after field 'm_kind' [-Werror,-Wreorder]
    : cvclass(std::move(c)),
      ^
third_party/llvm/llvm/tools/lldb/source/Plugins/SymbolFile/NativePDB/PdbUtil.cpp:51:14: error: field 'cvclass' is uninitialized when used here [-Werror,-Wuninitialized]
      m_kind(cvclass.Kind == TypeRecordKind::Struct ? Struct : Class) {}

llvm-svn: 346435