Handle binary keys of different lengths in update pipeline

[ajcvickers]

Fixes #16888

Note that StructuralEqualityComparer.Equals does not suffer from this problem.

[jjxtra]

Possible issue: It looks like the commit is comparing byte array lengths, this may not be correct. You need to compare bytes still, but if the smaller byte array is equal to the larger array up to it's length (like a substring), then it is less than the larger byte array, otherwise if the smaller byte array has a byte greater than the larger byte array at the same index, it is greater than.

Of course I could be misunderstanding something...

[ajcvickers]

@jjxtra All we need is a consistent ordering. What functional issue would it fix to do what you suggest?

[jjxtra]

I don’t know enough about the guts of entity framework to know. Just raising a possible problem...