Multiple tests failing for R2021a

[adrianhauber]

The following tests fail in MATAB R2021a (on macOS 11.3):

• DallaMan2007_GlucoseInsulinSystem
• TurboSplines
• State_Reduction
• Fast_Equilibration
• Boehm_JProteomeRes2014
• PEtab_Tests

[niklasneubrand]

I fixed the PEtab_Test. There were bugs in the code. At least on windows with MATLAB R2022b the tests work again.
I did not check the other tests.