Fix WorkspaceFactory outputting workspaces with an invalid vertical axis

[DanNixon]

Fixes #12720

I can't think of an easy way to test it other then via code review.

The issue is that differentSize boolean is set false by the create function as it sees that the Y length parameter is the default so it assumes the size does not change.

In the axis code it takes either this boolean flag being false or the axis lengths being identical to assume that the axis length had not changed, which only worked for the X axis.

No release note changes as this is an internal only issue.

[FedeMPouzols]

@DanNixon : The system test CalMuonDeadTimeTest seems not to like this PR. This test is comparing the output of the algorithm CalMuonDeadTime with a file previously saved file. It could well be that the reference file needs an update?

[DanNixon]

@FedeMPouzols I don't think it fails reliably though, I'm sure I have seen a build where is passed (I thought it was the second to last but I can't seem to see that build any more).

I'll have a better look tomorrow.

[FedeMPouzols]

I just tried a rebuid, to see if the maybe? random issue had vanished away after a few days, but it failed again on the same CalMuonDeadTimeTest.

[DanNixon]

Yes, there does seem to be some issue with it.
I have no idea what it is though, when I load the reference file and compare it to the result of me manually running the test they are identical.

[martyngigg]

Can this be pushed back to 3.7?