When an OutgoingMessage is closed (for example, using the `end`
method), its 'writable' property should be changed to false - since it
is not writable anymore. The 'writable' property should have the
opposite value of the 'finished' property.
PR-URL: https://github.com/nodejs/node/pull/14024
Fixes: https://github.com/nodejs/node/issues/14023
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
