net: make two tests not parallel
net: make two tests not parallel

Running

stress -p 1 go test -short std

on a heavily loaded machine causes net timeouts
every 15 or 20 runs.
Making these tests not run in parallel helps.
With this change, I haven’t seen a single failure
in over 100 runs.

Fixes #14986

Change-Id: Ibaa14869ce8d95b00266aee94d62d195927ede68
Reviewed-on: https://go-review.googlesource.com/21905
Run-TryBot: Josh Bleecher Snyder <cdc248cc4d32e4fbfe04e45228163bcecd48a0b9@gmail.com>
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

4ad/go,ganboing/go-esx,codestation/go,4ad/go,polyverse-security/go,josharian/go,ganboing/go-esx,ImJasonH/go,golang/go,cloudflare/go,4ad/go,vanloswang/go,linux-on-ibm-z/go,CAFxX/go,Cofyc/go,vanloswang/go,polyverse-security/go,Cofyc/go,goodlang/good,vsekhar/elastic-go,momchil-velikov/go,momchil-velikov/go,CAFxX/go,ganboing/go-esx,akutz/go,4ad/go,CAFxX/go,vanloswang/go,Cofyc/go,josharian/go,cloudflare/go,derekmarcotte/go,ImJasonH/go,vanloswang/go,linux-on-ibm-z/go,codestation/go,vanloswang/go,4ad/go,linux-on-ibm-z/go,4ad/go,cloudflare/go,vsekhar/elastic-go,akutz/go,nawawi/go,nawawi/go,suncycheng/go,akutz/go,derekmarcotte/go,ganboing/go-esx,cloudflare/go,codestation/go,akutz/go,golang/go,golang/go,nawawi/go,nawawi/go,codestation/go,suncycheng/go,akutz/go,theif519/go,vanloswang/go,christopher-henderson/Go,suncycheng/go,polyverse-security/go,derekmarcotte/go,ganboing/go-esx,polyverse-security/go,derekmarcotte/go,goodlang/good,derekmarcotte/go,goodlang/good,polyverse-security/go,akutz/go,theif519/go,ImJasonH/go,polyverse-security/go,cloudflare/go,vanloswang/go,vanloswang/go,akutz/go,Cofyc/go,4ad/go,vsekhar/elastic-go,Cofyc/go,linux-on-ibm-z/go,momchil-velikov/go,nawawi/go,derekmarcotte/go,CAFxX/go,suncycheng/go,nawawi/go,golang/go,ganboing/go-esx,ganboing/go-esx,CAFxX/go,josharian/go,goodlang/good,theif519/go,momchil-velikov/go,momchil-velikov/go,golang/go,linux-on-ibm-z/go,codestation/go,theif519/go,polyverse-security/go,nawawi/go,derekmarcotte/go,linux-on-ibm-z/go,theif519/go,vsekhar/elastic-go,ImJasonH/go,vsekhar/elastic-go,cloudflare/go,momchil-velikov/go,4ad/go,codestation/go,goodlang/good,cloudflare/go,golang/go,Cofyc/go,linux-on-ibm-z/go,CAFxX/go,vsekhar/elastic-go,golang/go,goodlang/good,nawawi/go,josharian/go,suncycheng/go,derekmarcotte/go,vsekhar/elastic-go,goodlang/good,goodlang/good,Cofyc/go,suncycheng/go,josharian/go,polyverse-security/go,theif519/go,suncycheng/go,ImJasonH/go,josharian/go,cloudflare/go,ImJasonH/go,codestation/go,josharian/go,suncycheng/go,CAFxX/go,linux-on-ibm-z/go,vsekhar/elastic-go,akutz/go,golang/go,ImJasonH/go,theif519/go,Cofyc/go,codestation/go,ganboing/go-esx,CAFxX/go,theif519/go,josharian/go,momchil-velikov/go,ImJasonH/go,momchil-velikov/go