message: Clang's ASTImport now returns Expected<> Types
  Clang changed Import to return an Expected<QualType> so updated the
  usage to match
  Clang was changed here:
diff: @@ -1437,8 +1437,13 @@ CompilerType ClangASTContext::CopyType(const CompilerType &src) {
  FileManager file_manager(file_system_options);
  ASTImporter importer(*dst_clang_ast, file_manager, *src_clang_ast,
  file_manager, false);
  - QualType dst_qual_type(importer.Import(ClangUtil::GetQualType(src)));
  + if (auto expected = importer.Import(ClangUtil::GetQualType(src))) {
  + QualType dst_qual_type(expected.get());
  return CompilerType(this, dst_qual_type.getAsOpaquePtr());
  + } else {
  + Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS);
  + LLDB_LOG_ERROR(log, expected.takeError(), "Couldn't import type: {0}");
  + }
  }
  }
  }
  