Function recanonicalize

src/compute-engine/rubi/normal-form.ts:231–237

(ce: ComputeEngine, e: Expression)

 * arithmetic produces unfolded artifacts (e.g. `a + 0·b`).
 */
export function recanonicalize(ce: ComputeEngine, e: Expression): Expression {
  if (e.symbol || !e.ops) return e;
  return ce.function(
    e.operator,
    e.ops.map((o) => recanonicalize(ce, o))
  );
}

function leafCountOf(e: Expression): number {
  if (!e.ops) return 1;