Focus and blur issues

[RaoHai]

• close select 选中option，调用select的focus事件 ant-design/ant-design#5741
• close Select's onFocus is not properly triggered ant-design/ant-design#5792
• close when option showSearch is true, select focus event not behaving normally ant-design/ant-design#5778

There's a confusing onFocus flow:

Focus <Select />, onFocus trigger.

• <Trigger/> focus
• <div /> focus,
• onOuterFocus() => props.onFocus() // Select onFocus callback here
• setPopupVisible() =>Trigger.onPopupVisibleChange() => setOpenState(true)
• <input /> get focus.

Focus <input />, onFocus not trigger

• <Trigger /> focus
• <input /> focus,
• setPopupVisible() =>Trigger.onPopupVisibleChange() => setOpenState(true)
• <input /> already focus, do nothing.

[coveralls]

Coverage decreased (-0.5%) to 95.254% when pulling 5f47f8d on RaoHai:FocusAndBlurIssues into 7b59a7d on react-component:master.