StateSpaceSimTest is Missing State Space Sim Tests

[modelmat]

Describe the bug https://github.com/wpilibsuite/allwpilib/blob/main/wpilibc/src/test/native/cpp/simulation/StateSpaceSimTest.cpp only has the one test of flywheelSim. Add the rest.

To Reproduce Steps to reproduce the behavior:

1. Watch intently at your screen and observe the existence of only one test
2. Existential dread

Expected behavior There be tests.

Screenshots No.

[modelmat]

It seems that:

• https://github.com/wpilibsuite/allwpilib/blob/main/wpilibc/src/test/native/cpp/simulation/SingleJointedArmSimTest.cpp
• https://github.com/wpilibsuite/allwpilib/blob/main/wpilibc/src/test/native/cpp/simulation/ElevatorSimTest.cpp

exist, so I think it would be better to rename StateSpaceSimTest to FlywheelSimTest and remove the includes.

Also Java doesn't have this test or the FlywheelSimTest

[calcmogul]

Yep. We should fix that.