Reland "HttpCache: fix troubles trying to do ranges with empty bodies"

This is a reland of commit bf289d66c255355a5524d5a2e7583e46135b2c5a

Original change's description:
> HttpCache: fix troubles trying to do ranges with empty bodies
>
> In FixResponseHeaders(), don't try to construct a Range: header when we have an empty body, since that can't represent an empty interval, just remove it and add a Content-Length:0 instead. Also only convert 206s to 200, not other things.
>
> In ShouldValidateCache(), make sure to treat empty body as EOF.
>
> Bug: 1375128, 813061
> Change-Id: I10a50cdf468c17c97b95eb91c09cc43bd8dad262
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4210436
> Commit-Queue: Maks Orlovich <morlovich@chromium.org>
> Reviewed-by: Shivani Sharma <shivanisha@chromium.org>
> Reviewed-by: Kenichi Ishibashi <bashi@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1103284}

Bug: 1375128, 813061
Change-Id: I98428c995bc7b3824f0e41dcb14cd0955237042d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4472488
Commit-Queue: Maks Orlovich <morlovich@chromium.org>
Commit-Queue: Kenichi Ishibashi <bashi@chromium.org>
Code-Coverage: Findit <findit-for-me@appspot.gserviceaccount.com>
Reviewed-by: Maks Orlovich <morlovich@chromium.org>
Auto-Submit: Adam Rice <ricea@chromium.org>
Reviewed-by: Kenichi Ishibashi <bashi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1135321}

• net/http/http_cache_unittest.cc[diff]
• net/http/partial_data.cc[diff]