wallFunctions use cornerWeights inside non-linear functions

Summary

in e.g. omegaWallFunction the cornerWeights (used to accumulate contributions from multiple wall patches on a single cell) are applied inside a (sometimes non-linear) function. This looks incorrect.

Steps to reproduce

Visual inspection.

• generate a mesh with cells that have faces on multiple patches. E.g. motorBike tutorial.
• take the resulting mesh and create a copy where all the motorBike patches get merged into a single patch
• compare a single iteration (e.g. simpleFoam) between the two
• there is no difference with 'stepwise' blending but there is with e.g. 'binomial'

Example case

motorBike tutorial

What is the current bug behaviour?

Differences between single patch or multiple patches

What is the expected correct behavior?

No difference

Relevant logs and/or images

Environment information

• OpenFOAM version : use #3215 branch (fixes similar problem for wall distance)
• Operating system :
• Hardware info :
• Compiler :

Possible fixes

Apply cornerWeights after evaluating non-linear function? @kuti