Avoid downloading go toolchain whenever go/def.bzl changes (#85)
Avoid downloading go toolchain whenever go/def.bzl changes (#85)

The issue was introduced at 4c2efe6cca58555e0cf333224c02298a08274bbb
This commit reverts a part of 4c2efe6cca58555e0cf333224c02298a08274bbb
to let Bazel manage go toolchain archive, but it still resolves a tool
chain for the current build platform in the analysis phase.
bazelbuild/rules_go,Xjs/rules_go,Xjs/rules_go,Xjs/rules_go,Xjs/rules_go,Xjs/rules_go,bazelbuild/rules_go,linuxerwang/rules_go,bazelbuild/rules_go,linuxerwang/rules_go,bazelbuild/rules_go,linuxerwang/rules_go,linuxerwang/rules_go,bazelbuild/rules_go,linuxerwang/rules_go