VTests: drop superficial calls to buildTangentVectors on knot.mesh
VTests: drop superficial calls to buildTangentVectors on knot.mesh

that somehow corrupted the vertex arrays in later tests on GL3+/ GLES2
OGRECave/ogre,paroj/ogre,OGRECave/ogre,paroj/ogre,OGRECave/ogre,paroj/ogre,paroj/ogre,OGRECave/ogre,OGRECave/ogre,paroj/ogre