net: make TestInterfaceList work on non-English Windows
net: make TestInterfaceList work on non-English Windows

Fixes #13198

The output of netsh is encoded with ANSI encoding. So doesn't match with UTF-8 strings.
Write output as UTF-8 using powershell.

Change-Id: I6c7e93c590ed407f24ae847601d71df9523e028c
Reviewed-on: https://go-review.googlesource.com/16756
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Alex Brainman <54ba58c8441b5eff861de6b4e5ee46baf086b142@gmail.com>

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