Tangents likely incorrect for a couple meshes in two test assets

[emackey]

Following the changes in #135, some test meshes were given TANGENT mesh attributes that may have been calculated from TEXCOORD_1 instead of TEXCOORD_0. The assets in question are testing UV selection, not tangent space, so tests can still pass. But it might be nice to clean up the tangent attributes on the affected models, ClearCoatTest and TextureTransformMultiTest.