fs: replace finally with PromisePrototypeFinally
See suggestion here- https://github.com/nodejs/node/pull/35993#discussion_r518703665
Checklist
-
make -j4 test(UNIX), orvcbuild test(Windows) passes -
commit message follows commit guidelines
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
See suggestion here- https://github.com/nodejs/node/pull/35993#discussion_r518703665
make -j4 test (UNIX), or vcbuild test (Windows) passes