Avoiding recursive call would imply iterating bits starting from
most significant, which is not easy to do efficiently.
Any saving would be dwarfed by the multiplications anyways.
[Feature #15233]

Patch adapted from Alessandro Minali

```
 % RBENV_VERSION=2.6.5 ruby -r matrix -e 'Vector[1]*Vector[2] rescue p($!)'
 #<ExceptionForMatrix::ErrOperationNotDefined: Operation(*) can't be defined: Vector op Vector>
 % RBENV_VERSION=2.7.0 ruby -r matrix -e 'Vector[1]*Vector[2] rescue p($!)'
 #<ExceptionForMatrix::ErrOperationNotDefined: Operation(*) can\'t be defined: Vector op Vector>
 % RBENV_VERSION=master ruby -r matrix -e 'Vector[1]*Vector[2] rescue p($!)'
 #<ExceptionForMatrix::ErrOperationNotDefined: Operation(*) can't be defined: Vector op Vector>
```