cmd/go: remove fips140 dependency on global Fetcher_
This commit makes Unzip a method on the *Fetcher type, and updates
fips140 initialization to use a new Fetcher instance instead of the
global Fetcher_ variable.
Change-Id: Iea8d9ee4dd6e6a2be43520c144aaec6e75c9cd63
Reviewed-on: https://go-review.googlesource.com/c/go/+/722581
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Matloob <matloob@google.com>