[v6.x backport] tls: fix writeQueueSize prop, long write timeouts

This is a backport of https://github.com/nodejs/node/pull/15791 as requested.

/cc @MylesBorins

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• commit message follows commit guidelines

Affected core subsystem(s)

net, tls, test