gost: fix test (#70575)
gost: fix test (#70575)

Addresses https://github.com/Homebrew/homebrew-core/pull/70446#issuecomment-774334533

For future reference, this is what `curl` actually dumps during the test:
```
HTTP/1.1 200 Connection established
Proxy-Agent: gost/2.11.1

HTTP/2 200
content-type: text/html
content-length: 123345
date: Sat, 06 Feb 2021 03:43:03 GMT
last-modified: Sat, 06 Feb 2021 03:40:54 GMT
etag: "c5586663e2daefdbbd076e1e7faa4b2e"
server: AmazonS3
vary: Accept-Encoding
x-cache: Hit from cloudfront
via: 1.1 cc2beda7b70d44b6ed40dda2c22f45e5.cloudfront.net (CloudFront)
x-amz-cf-pop: SIN52-C3
x-amz-cf-id: QmqjFnkODEcFmdgropHcMGkdVXgFDmLzfqq78zoZkr6g77oIBtSlCQ==
age: 24848
```
JCount/homebrew-core,sjackman/homebrew-core,mfikes/homebrew-core,nbari/homebrew-core,Moisan/homebrew-core,uyjulian/homebrew-core,lemzwerg/homebrew-core,nandub/homebrew-core,mfikes/homebrew-core,uyjulian/homebrew-core,spaam/homebrew-core,stgraber/homebrew-core,makigumo/homebrew-core,adam-moss/homebrew-core,lemzwerg/homebrew-core,Moisan/homebrew-core,sjackman/homebrew-core,nandub/homebrew-core,stgraber/homebrew-core,cblecker/homebrew-core,chrisfinazzo/homebrew-core,cblecker/homebrew-core,JCount/homebrew-core,mbcoguno/homebrew-core,Homebrew/homebrew-core,mbcoguno/homebrew-core,adam-moss/homebrew-core,spaam/homebrew-core,makigumo/homebrew-core,filcab/homebrew-core,mbcoguno/homebrew-core,nbari/homebrew-core,Homebrew/homebrew-core,dsXLII/homebrew-core,Linuxbrew/homebrew-core,chrisfinazzo/homebrew-core,zyedidia/homebrew-core,filcab/homebrew-core,zyedidia/homebrew-core,dsXLII/homebrew-core,Linuxbrew/homebrew-core