[release-branch.go1.11] net/http: ensure null body in Fetch response is not read
The Fetch API returns a null body if there is no response body,
on browsers that support streaming the response body. This
change ensures we check for both undefined and null bodies
before attempting to read the body.
Fixes #27424
Change-Id: I0da86b61284fe394418b4b431495e715a037f335
Reviewed-on: https://go-review.googlesource.com/131236
Reviewed-by: Richard Musiol <neelance@gmail.com>
Run-TryBot: Richard Musiol <neelance@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
(cherry picked from commit
ce536837d8e53f1bf0c7ef450d4580d19f7d6f52)
Reviewed-on: https://go-review.googlesource.com/136915