Better downgrade CI

[ErikQQY]

Remove the old downgrade CIs in test actions, and force the new downgrade CIs use 1.11

[github-actions]

Benchmark Results

Click to check benchmark results

	master	ccdf3a6...	master / ccdf3a6...
Simple Pendulum/IIP/BoundaryValueDiffEqMIRK.MIRK2()	0.578 ± 0.013 s	0.581 ± 0.016 s	0.996 ± 0.036
Simple Pendulum/IIP/BoundaryValueDiffEqMIRK.MIRK3()	13.6 ± 0.54 ms	13.7 ± 0.58 ms	0.996 ± 0.058
Simple Pendulum/IIP/BoundaryValueDiffEqMIRK.MIRK4()	3.15 ± 0.16 ms	3.14 ± 0.21 ms	1 ± 0.086
Simple Pendulum/IIP/BoundaryValueDiffEqMIRK.MIRK5()	9.29 ± 1.3 ms	9.3 ± 1.3 ms	0.999 ± 0.2
Simple Pendulum/IIP/BoundaryValueDiffEqMIRK.MIRK6()	1.62 ± 0.27 ms	1.63 ± 0.28 ms	0.991 ± 0.24
Simple Pendulum/IIP/MultipleShooting(10, Tsit5; grid_coarsening = false)	1.84 ± 0.67 ms	1.85 ± 0.64 ms	0.999 ± 0.5
Simple Pendulum/IIP/MultipleShooting(10, Tsit5; grid_coarsening = true)	3.09 ± 1 ms	3.12 ± 1 ms	0.991 ± 0.45
Simple Pendulum/IIP/MultipleShooting(100, Tsit5; grid_coarsening = false)	0.0654 ± 0.0067 s	0.0659 ± 0.0073 s	0.993 ± 0.15
Simple Pendulum/IIP/MultipleShooting(100, Tsit5; grid_coarsening = true)	0.0785 ± 0.007 s	0.0792 ± 0.0075 s	0.991 ± 0.13
Simple Pendulum/IIP/Shooting(Tsit5())	0.237 ± 0.078 ms	0.235 ± 0.076 ms	1.01 ± 0.46
Simple Pendulum/OOP/BoundaryValueDiffEqMIRK.MIRK2()	0.729 ± 0.0044 s	0.73 ± 0.0022 s	0.998 ± 0.0067
Simple Pendulum/OOP/BoundaryValueDiffEqMIRK.MIRK3()	16.6 ± 4.9 ms	16.4 ± 4.9 ms	1.01 ± 0.43
Simple Pendulum/OOP/BoundaryValueDiffEqMIRK.MIRK4()	3.61 ± 0.15 ms	3.59 ± 0.13 ms	1.01 ± 0.054
Simple Pendulum/OOP/BoundaryValueDiffEqMIRK.MIRK5()	10.6 ± 0.99 ms	10.7 ± 1.4 ms	0.989 ± 0.16
Simple Pendulum/OOP/BoundaryValueDiffEqMIRK.MIRK6()	1.87 ± 0.16 ms	1.86 ± 0.13 ms	1 ± 0.11
Simple Pendulum/OOP/MultipleShooting(10, Tsit5; grid_coarsening = false)	3.49 ± 2.9 ms	3.52 ± 2.9 ms	0.991 ± 1.2
Simple Pendulum/OOP/MultipleShooting(10, Tsit5; grid_coarsening = true)	5.91 ± 4.9 ms	5.97 ± 4.9 ms	0.99 ± 1.2
Simple Pendulum/OOP/MultipleShooting(100, Tsit5; grid_coarsening = false)	0.116 ± 0.0043 s	0.116 ± 0.003 s	1 ± 0.045
Simple Pendulum/OOP/MultipleShooting(100, Tsit5; grid_coarsening = true)	0.145 ± 0.0051 s	0.141 ± 0.0039 s	1.02 ± 0.045
Simple Pendulum/OOP/Shooting(Tsit5())	0.625 ± 0.035 ms	0.632 ± 0.038 ms	0.99 ± 0.082
time_to_load	5.5 ± 0.015 s	5.39 ± 0.018 s	1.02 ± 0.0044

### Benchmark Plots A plot of the benchmark results has been uploaded as an artifact to the workflow run for this PR. Go to "Actions"->"Benchmark a pull request"->[the most recent run]->"Artifacts" (at the bottom).

[ChrisRackauckas]

The CI is working well now. I have to do a few things upstream for it to pass.