TaskManager: Remove the explicit use of Core::Id::toUniqueIdentifier()
TaskManager: Remove the explicit use of Core::Id::toUniqueIdentifier()

Directly comparing the Ids gives the same effect of a stable
(but unpredictable) sort.

Change-Id: Iaf54a127b02f2a89eeff9b6d008575bb899ef926
Reviewed-by: Daniel Teske <d8a411aec9a206efedb4d45b75fe8d13f1e2b628@theqtcompany.com>

xianian/qt-creator,martyone/sailfish-qtcreator,xianian/qt-creator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,xianian/qt-creator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,xianian/qt-creator,xianian/qt-creator,xianian/qt-creator,martyone/sailfish-qtcreator,xianian/qt-creator,xianian/qt-creator,xianian/qt-creator,martyone/sailfish-qtcreator