Revert "[LayoutNG] Remove spaces before <br> to avoid crbug.com/40634"

This reverts commit 6ec9b32f0008c9cdafa6402aefdb3846b3838e50.

Reason for revert: <INSERT REASONING HERE>

svg/as-border-image/svg-as-border-image.html / svg/as-border-image/svg-as-border-image-2.html have been failing since https://ci.chromium.org/buildbot/chromium.webkit/WebKit%20Mac10.13%20%28retina%29/65
Original change's description:
> [LayoutNG] Remove spaces before <br> to avoid crbug.com/40634
> 
> This patch removes spaces before <br> because the images do
> not match due to crbug.com/40634, which LayoutNG does not
> have the problem.
> 
> TBR=eae@chromium.org
> 
> Bug: 591099
> Change-Id: I8f0770f8911ce2d5c6f9e37ff90752011b84cb49
> Reviewed-on: https://chromium-review.googlesource.com/1142050
> Reviewed-by: Koji Ishii <kojii@chromium.org>
> Commit-Queue: Koji Ishii <kojii@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#576333}

TBR=eae@chromium.org,kojii@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 591099
Change-Id: Iaeae508ed67354b06beec60704fdb0da5021bd34
Reviewed-on: https://chromium-review.googlesource.com/1148807
Reviewed-by: Derek Cheng <imcheng@chromium.org>
Commit-Queue: Derek Cheng <imcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577652}
18 files changed