Unify calls to profiler service event methods.

Don't needlessly duplicate information about the profiler being available
and allow inlining. Use macros to check availability of the profiler
in calling code and generally simplify the code.

Task-number: QTBUG-35315
Change-Id: I0a9daec4a95f74b9db795ef2918a01fb772ea107
Reviewed-by: Michael Brasser <michael.brasser@live.com>
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Reviewed-by: Kai Koehne <kai.koehne@digia.com>