This reverts CL 544019 and CL 569815, because they break a variety
of tests inside Google that do not expect the Cache-Control header
to be set to no-cache.
A followup CL will add this functionality back after a proposal.
For #50905.
Change-Id: Ie377bfb72ce2c77d11bf31f9617ab6db342a408a
Reviewed-on: https://go-review.googlesource.com/c/go/+/571975
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Cherry Mui <cherryyz@google.com> Reviewed-by: Michael Knyszek <mknyszek@google.com>