BREAKING: change in behaviour for faPatch/fvPatch patchInternalField()

- the output parameter was previously a field and resized according to
  the patch size. Now the output parameter must be pre-sized prior to
  calling, which makes it possible to collect the patch internal
  fields into slices of a larger list.

  Signatures:

      void patchInternalField
      (
          const UList<Type>& internalData,
          UList<Type>& pfld    // OLD: Field<Type>& pfld
      ) const;

      void patchInternalField
      (
          const UList<Type>& internalData,
          const labelUList& addressing,
          UList<Type>& pfld    // OLD: Field<Type>& pfld
      ) const;

  This low-level change is not expected to affect any user code,
  which would normally use a higher-level interface such as from
  fvPatchField etc.