Run them separately from the other tests in godoc_test by requiring a
regtest.host flag and by filtering on the test name.
Updates golang/go#27205.
Change-Id: I166d2278a3f6954307f7c935567a81e73f78e7bb
Reviewed-on: https://go-review.googlesource.com/c/139238
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Chris Broadfoot