Run tests in CI on both Windows and Linux

[yel0h]

Split the CI workflow's zig build test step out of the compile job into its own test job that runs on a matrix, so unit tests execute on both operating systems.

Closes #3535

[IntegratedQuantum]

Would you mind also checking if we can get it running on macos as well?

[yel0h]

We sure can, however currently Mac fails to compile due to #3541

[IntegratedQuantum]

Alright, then lets do it without macos first, it's good to know that it's at least possible in principle

[IntegratedQuantum]

Also, after seeing that each of them takes several minutes again (whereas in the main CI job it took only a few seconds to compile and run the tests), I think we should do the platform specific compilation in the same CI unit as the tests, to avoid duplicated dependency downloads.

The main CI unit would then only do the format checking and shader compilation

[yel0h]

Done

[Wunka]

can you not just use:

Suggested change

	- if: matrix.os == 'ubuntu-latest'
	run: zig build -Dtarget=aarch64-linux-gnu
	- if: matrix.os == 'windows-latest'
	run: zig build -Dtarget=aarch64-windows-gnu
	run: zig build -Dtarget=aarch64-native-gnu

[IntegratedQuantum]

If that's possible we should also change the default one to -Dtarget=x86_64-native

[yel0h]

Ok, replaced the ifs with a native target

[IntegratedQuantum]

gnu shouldn't be needed here. It also would be incorrect when we want to extend this for macos.

[yel0h]

Unfortunately it seems gnu needs to say, leaving it out tries to use the native x86_64 headers...

[IntegratedQuantum]

Ah I see, I guess we will need to go back to ifs once we implement macos then. Either way it's probably fine for now.

Though it seems that the CI is failing now, not sure why. I also tried restarting it with the same results. Please investigate.