Remove unnecessary code after latest changes to instance management

src/Meshes/mesh.ts

@@ -3002,10 +3002,6 @@ export class Mesh extends AbstractMesh implements IGetSetVerticesData {
      * @returns the current mesh
      */
     public synchronizeInstances(): Mesh {
-        if (this._geometry && this._geometry.meshes.length !== 1 && this.instances.length) {
-            this.makeGeometryUnique();
-        }
-
         for (var instanceIndex = 0; instanceIndex < this.instances.length; instanceIndex++) {
             var instance = this.instances[instanceIndex];
             instance._syncSubMeshes();