Disable webkit3d on android 2/3 because it is buggy as

We almost always just used top/left on old android anyway. Now we always do.
This should fix any 3d related issues as we no longer even use it on old android.
Drag performance seems the same to me.

Tested on 2.3.4 + 4.1.2 + 4.2.2 stock browsers and android 4.4 chrome.

Fixes #2198