[js/webgpu] Optimize broadcast binary. (#18185)
### Description
Currently, the binary algorithms are divided into the vectorize one
(efficient) and non-vectorize one (less efficient). Below situations
will go to the vectorize one:
1) A or B's shape length is 1.
2) The shared dimensions length of A and B are divisible by 4.
3) A and B have same shape.
This PR adds another situation as below to go to the vectorize
algorithm.
4. A or B's last dimension is divisible by 4.
With this change, the aggerate time of Add in sam-b-encoder becomes
309.65 ms from 409.12 ms on Intel ADL.
