net: reorganize interface tests to avoid vague flakiness
net: reorganize interface tests to avoid vague flakiness

This change reorganizes test cases for surveying network interfaces and
address prefixes to make sure which part of the functionality is broken.

Updates #7849.

Change-Id: If6918075802eef69a7f1ee040010b3c46f4f4b97
Reviewed-on: https://go-review.googlesource.com/22990
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

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