os: read only 10,000 bytes at a time from Windows console
os: read only 10,000 bytes at a time from Windows console

Reading 32,767 is too many on some versions of Windows.
The exact upper bound is unclear.

For #13697, but may not fix the problem on all systems.

Change-Id: I197021ed60cbcd33c91ca6ceed456ec3d5a6c9d6
Reviewed-on: https://go-review.googlesource.com/18433
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

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