net/http: maybe deflake TestCancelRequestMidBody_h2 on linux-noopt builder
net/http: maybe deflake TestCancelRequestMidBody_h2 on linux-noopt builder

This might deflake it. Or it'll at least give us more debugging clues.

Fixes #13626 maybe

Change-Id: Ie8cd0375d60dad033ec6a64830a90e7b9152a3d9
Reviewed-on: https://go-review.googlesource.com/17825
Reviewed-by: Austin Clements <7ea35d812706d9213868749011af1ed4fa2f6aa0@google.com>
Run-TryBot: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

sndnvaps/go,binarycrusader/go,codestation/go,vanloswang/go,linux-on-ibm-z/go,ganboing/go-esx,vanloswang/go,goodlang/good,ImJasonH/go,nawawi/go,kim-racktop/go,vsekhar/elastic-go,cloudflare/go,sndnvaps/go,4ad/go,Endika/go,akutz/go,cyberroadie/go,miolini/go,linux-on-ibm-z/go,cloudflare/go,theif519/go,CAFxX/go,vsekhar/elastic-go,vanloswang/go,ganboing/go-esx,vanloswang/go,binarycrusader/go,nawawi/go,Cofyc/go,josharian/go,deft-code/go,codestation/go,ganboing/go-esx,linux-on-ibm-z/go,CAFxX/go,Cofyc/go,ganboing/go-esx,ImJasonH/go,kim-racktop/go,goodlang/good,roth1002/go,Samurais/go,deft-code/go,momchil-velikov/go,suncycheng/go,derekmarcotte/go,roth1002/go,vsekhar/elastic-go,codestation/go,cyberroadie/go,Cofyc/go,miolini/go,cloudflare/go,Samurais/go,linux-on-ibm-z/go,kim-racktop/go,vsekhar/elastic-go,polyverse-security/go,codestation/go,kim-racktop/go,sndnvaps/go,sndnvaps/go,josharian/go,polyverse-security/go,Samurais/go,linux-on-ibm-z/go,kim-racktop/go,4ad/go,josharian/go,momchil-velikov/go,miolini/go,miolini/go,momchil-velikov/go,mwhudson/go,theif519/go,binarycrusader/go,suncycheng/go,akutz/go,suncycheng/go,ImJasonH/go,4ad/go,linux-on-ibm-z/go,josharian/go,Samurais/go,cyberroadie/go,CAFxX/go,cyberroadie/go,derekmarcotte/go,ganboing/go-esx,golang/go,kim-racktop/go,suncycheng/go,sndnvaps/go,polyverse-security/go,polyverse-security/go,cyberroadie/go,akutz/go,ImJasonH/go,deft-code/go,akutz/go,miolini/go,CAFxX/go,golang/go,ImJasonH/go,miolini/go,akutz/go,ganboing/go-esx,goodlang/good,goodlang/good,ImJasonH/go,CAFxX/go,momchil-velikov/go,mwhudson/go,vanloswang/go,derekmarcotte/go,codestation/go,Endika/go,roth1002/go,deft-code/go,cloudflare/go,derekmarcotte/go,codestation/go,momchil-velikov/go,theif519/go,cyberroadie/go,mwhudson/go,goodlang/good,golang/go,Samurais/go,vanloswang/go,theif519/go,nawawi/go,akutz/go,4ad/go,nawawi/go,Endika/go,vsekhar/elastic-go,Cofyc/go,roth1002/go,Endika/go,nawawi/go,golang/go,cloudflare/go,josharian/go,CAFxX/go,suncycheng/go,theif519/go,deft-code/go,polyverse-security/go,vsekhar/elastic-go,4ad/go,polyverse-security/go,cyberroadie/go,kim-racktop/go,cloudflare/go,akutz/go,mwhudson/go,josharian/go,CAFxX/go,binarycrusader/go,momchil-velikov/go,Samurais/go,vanloswang/go,momchil-velikov/go,vanloswang/go,binarycrusader/go,goodlang/good,polyverse-security/go,josharian/go,roth1002/go,roth1002/go,binarycrusader/go,sndnvaps/go,theif519/go,miolini/go,vsekhar/elastic-go,ImJasonH/go,mwhudson/go,ganboing/go-esx,derekmarcotte/go,Endika/go,4ad/go,Samurais/go,roth1002/go,goodlang/good,deft-code/go,miolini/go,derekmarcotte/go,deft-code/go,Samurais/go,kim-racktop/go,mwhudson/go,ImJasonH/go,akutz/go,cloudflare/go,Cofyc/go,roth1002/go,christopher-henderson/Go,cyberroadie/go,derekmarcotte/go,suncycheng/go,theif519/go,nawawi/go,suncycheng/go,4ad/go,Cofyc/go,codestation/go,momchil-velikov/go,vsekhar/elastic-go,sndnvaps/go,Endika/go,cloudflare/go,ganboing/go-esx,4ad/go,binarycrusader/go,Endika/go,sndnvaps/go,suncycheng/go,polyverse-security/go,golang/go,Cofyc/go,linux-on-ibm-z/go,mwhudson/go,golang/go,CAFxX/go,josharian/go,mwhudson/go,nawawi/go,goodlang/good,binarycrusader/go,nawawi/go,golang/go,linux-on-ibm-z/go,codestation/go,Endika/go,Cofyc/go,deft-code/go,golang/go,derekmarcotte/go,theif519/go