tcp: partially undo D43792

[rscheff]

Summary

At the destruction of the tcpcb, no timers are supposed to
be running. However, it turns out that stopping them in the
close() / shutdown() call does not have the desired effect
under all circumstances.

This partially reverts 62d47d73b7eb to reduce the nuisance
caused.

Reported-by: [e-mail]
Reported-by: [e-mail]
PR: 277009

[glebius]

I'm fine with the change if we all agree it is a temporary measure.