Fix render tree creation in blocks with multiple anonymous blocks and mixed inlines/out of flow children

Out of flow children weren't being inserted into anonymous blocks following the same rules as inlines,
which had the effect of breaking a later search for the correct anonymous block to attach other
inline renderers in the middle of the containing block. This had the effect of the resulting inlines
being separated into different anonymous blocks (and hence visually) when they all should all be
siblings of the same anonymous block.

BUG=318839

Review URL: https://codereview.chromium.org/120603002

git-svn-id: svn://svn.chromium.org/blink/trunk@164278 bbb929c8-8fbe-4397-9dbb-9b2b20218538