functionObjects: Simplified the handling of the post-processing mode

Replaced the 'postProcess' argument to the 'write' and 'execute'
functions with the single static member 'postProcess' in the
functionObject base-class.

src/functionObjects/utilities/codedFunctionObject/codedFunctionObject.H

@@ -169,12 +169,12 @@ public:
         //- Called at each ++ or += of the time-loop.
         //  postProcess overrides the usual executeControl behaviour and
         //  forces execution (used in post-processing mode)
-        virtual bool execute(const bool postProcess = false);
+        virtual bool execute();
 
         //- Called at each ++ or += of the time-loop.
         //  postProcess overrides the usual writeControl behaviour and
         //  forces writing always (used in post-processing mode)
-        virtual bool write(const bool postProcess = false);
+        virtual bool write();
 
         //- Called when Time::run() determines that the time-loop exits.
         //  By default it simply calls execute().