Fixed tap is working when tap on left/right text selection handle above any linkable...

Fixed tap is working when tap on left/right text selection handle above any linkable content.

[Title] Fixed tap is working when tap on left/right text selection handle above any linkable content.
[Issue#] N_SE-34980
[Problem] When tap on left/right text selection handle above any linkable content,
          tap is working.
[Cause] If isTextSelectionHandleDowned() return value is true, _ewk_view_smart_gesture_end() is return.
        When _ewk_view_smart_gesture_end() is called, isTextSelectionHandleDowned() return value is false.
        So, tap is working.
[Solution] Changed routine to set isMouseDowned variable to false.

Change-Id: I5adf8518f6ce99bba3462806f785b95e98eb1370