node-api: factor out common code into macros

 * Create macro for checking new string arguments. * Create macro for combining env check and inside-gc check. PR-URL: #50664 Reviewed-By: Vladimir Morozov <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Chengzhong Wu <[email protected]>

Author: gabrielschulhof