[flang] Merge pull request flang-compiler/f18#119 from flang-compiler/pmk1

Use braces in `auto` initializers in lib/{parser,common,evaluate}

Original-commit: flang-compiler/f18@1aeba0c214b3a6388de630345eb5164749be598d
Reviewed-on: https://github.com/flang-compiler/f18/pull/119