Add tests to ensure coretime scheduler works with under-assigned cores

[seadanda]

Add regression tests to ensure the behaviour is maintained with future changes.

Originally posted by @seadanda in #6384 (comment)

[rainbow-promise]

Can I pick this up?

[seadanda]

@spanow was already working on the main issue, of which this is a part. Are you OK to give them a couple of days to reply before you take it on? It's likely they'll still be interested
There are other good issues to get started with while you wait :)

[rainbow-promise]

@spanow was already working on the main issue, of which this is a part. Are you OK to give them a couple of days to reply before you take it on? It's likely they'll still be interested There are other good issues to get started with while you wait :)

Yeah Thanks @seadanda

[seadanda]

@rainbow-promise if you're still interested it looks like @spanow didn't take this in the end

[rainbow-promise]

@rainbow-promise if you're still interested it looks like @spanow didn't take this in the end

Thanks for the heads up @seadanda, yes still interested.

I'll have a few more follow-up questions soon, while I look more into it.

Could you maybe drop relevant links if necessary.

[seadanda]

#6384 contains some details further to the PR linked above.

The aim is to add regression tests for the new functionality added in the PR