message: [ClangExpressionParser] Revert duplicated file creation logic
  We already create a temporary file directly below this code,
  so this seems redundant.
diff: @@ -830,24 +830,6 @@ ClangExpressionParser::ParseInternal(DiagnosticManager &diagnostic_manager,
  clang::SourceManager &source_mgr = m_compiler->getSourceManager();
  bool created_main_file = false;
  - /* Swift only */
  - if (m_expr.GetOptions() &&
  - m_expr.GetOptions()->GetPoundLineFilePath() == NULL &&
  - m_compiler->getCodeGenOpts().getDebugInfo() ==
  - codegenoptions::FullDebugInfo) {
  - std::string temp_source_path;
  - if (ExpressionSourceCode::SaveExpressionTextToTempFile(
  - expr_text, *m_expr.GetOptions(), temp_source_path)) {
  - auto file = m_compiler->getFileManager().getFile(temp_source_path);
  - if (file) {
  - source_mgr.setMainFileID(
  - source_mgr.createFileID(file, SourceLocation(), SrcMgr::C_User));
  - created_main_file = true;
  - }
  - }
  - }
  - /* end swift only */
  -
  // Clang wants to do completion on a real file known by Clang's file manager,
  // so we have to create one to make this work.
  // TODO: We probably could also simulate to Clang's file manager that there
  