Keep balancing "split" AppVeyor jobs

[alexcrichton]

@kennytm has done some amazing analysis and it looks like our "split" appveyor jobs for 32-bit tests currently isn't very split but rather still somewhat imbalanced. We should shuffle around some more test suites to balance the load a bit more!

[alexcrichton]

cc @rust-lang/infra

[bjorn3]

Is this still relevant?

[Mark-Simulacrum]

I don't think we need an issue for continuing to balance things, but we do still have some split builders (typically ending in -1, -2).