edje/textstyle/optimization: Optimize code as textblock style handle logic changes.

edje/textstyle/optimization: Optimize code as textblock style handle logic changes.

As tizen keeps a per object textblock style we don't
need to clear the file level textstyle as we never refer it. So cleanup the logic
which will be similar to opensource and performs much better than current logic.

Change-Id: I73905ee2e90a4e11496f902c04cbb7de9da38bb9