build: test linux/mips64 and linux/mips64le with buildall.bash
build: test linux/mips64 and linux/mips64le with buildall.bash

Both mips64 architectures share the same runtime/rt0 file, so
we have to hardcode them in buildall.bash.

Ideally we should have cmd/dist report all supported platforms,
see #12270.

Change-Id: I08ce35cfe0a831af5e1e8255b305efd38386fa52
Reviewed-on: https://go-review.googlesource.com/18687
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
Run-TryBot: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

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