Function tensor_consume 

pub fn tensor_consume(
    a: &mut NQuin,
    a_reusable: bool,
    b: &mut NQuin,
    b_reusable: bool,
) -> bool

A ⊗ B consumption: a tensor demand needs both operands available together. Consumes each linear operand (leaves reusable ones); returns false without mutating if either is already exhausted.