async_hooks: stabilize part of AsyncLocalStorage

Mark AsyncLocalStorage constructor,
AsyncLocalStorage.prototype.getStore(),
and AsyncLocalStorage.prototype.run as
stable.

PR-URL: #37675
Reviewed-By: Bradley Farias <[email protected]>
Reviewed-By: Andrey Pechkurov <[email protected]>
Reviewed-By: Michael Dawson <[email protected]>
Reviewed-By: Stephen Belanger <[email protected]>
Reviewed-By: Matteo Collina <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Gerhard Stöbich <[email protected]>
Reviewed-By: Chengzhong Wu <[email protected]>
Reviewed-By: Anna Henningsen <[email protected]>
Reviewed-By: Bryan English <[email protected]>