tcp: even localhost networking is extremely slow sometimes

[X512]

This is hrev57460.

Server:

python3 -m http.server --bind 0.0.0.0 80

Client:

/Haiku/data/distrib> wget -O - http://127.0.0.1/Fedora-Workstation-Live-x86_64-38-1.6.iso > /dev/null
--2023-12-29 05:51:44--  http://127.0.0.1/Fedora-Workstation-Live-x86_64-38-1.6.iso
Connecting to 127.0.0.1:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 2099451904 (2.0G) [application/octet-stream]
Saving to: 'STDOUT'

-                                0%[                                                  ]   4.44M   284KB/s    eta 2h 0m  

DD for reference:

/Haiku/data/distrib> dd if=/Haiku/data/distrib/Fedora-Workstation-Live-x86_64-38-1.6.iso of=/dev/null bs=1M
2002+1 records in
2002+1 records out
2099451904 bytes (2.1 GB, 2.0 GiB) copied, 0.199473 s, 10.5 GB/s