Revert of DevTools: Prefer nextSibling to previousSibling when moving treeElement selection after element rem… (patchset #3 id:40001 of https://codereview.chromium.org/764893002/)

Reason for revert:
Introduces a very flaky test.
http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=inspector%2Felements%2Felements-panel-selection-after-delete.html&testType=layout-tests

Original issue's description:
> DevTools: Prefer nextSibling to previousSibling when moving treeElement selection after element removal.
> 
> R=pfeldman
> NOTRY=true
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=186190

TBR=vsevik@chromium.org
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/768993002

git-svn-id: svn://svn.chromium.org/blink/trunk@186205 bbb929c8-8fbe-4397-9dbb-9b2b20218538