blockMesh with geometric point merging fails on high-aspect ratio cells

Summary

Run a case with very high aspect ratio cells. Sometimes this can trigger the geometric point merging to merge points (because it thinks it is generating a wedge geometry)

Steps to reproduce

blockMeshDict

run

blockMesh
checkMesh

and checkMesh reports 2 hexes. Now comment out the fastMerge and repeat. It will report two wedges.

This is a known problem of the geometric point merging - the topological fastMerge algorithm is also quicker to run.