CI workflow to perform automated testing with multithreading

[joshichaitanya3]

This PR attempts to add a CI workflow to run the test-suite with morpho6 -w2, thus checking for bugs with multithreading.

Given the increase in parallelization in Morpho (yay!), this could be quite useful to spot bugs like #259

It essentially adds one more argument flag to test.py and invokes it in the new workflow.

[softmattertheory]

This looks good. Suggested changes:

1. Change branches on lines 5, 7 to include "dev"

2. test.py lines 186 - 193 we can do something a bit more elegant, e.g.

for a in sys.argv:
    if a == '-c': 
        CI = True 
    elif a == '-w':
        # do something else 

3. line 198 append "-w4" to command:

command+="-w4" 

More threads are better to make a race condition more likely to appear.

[joshichaitanya3]

Great, thanks! I have fixed these.

1. Change branches on lines 5, 7 to include “dev"

I had copied this workflow from the buildandtest one, and it didn’t have dev too. Is that something we need to fix?

[softmattertheory]

I had copied this workflow from the buildandtest one, and it didn’t have dev too. Is that something we need to fix?

Good point: I already fixed it, but the fix is not in dev, it's in type. [See, e.g. https://github.com/Morpho-lang/morpho/blob/type/.github/workflows/nonanboxing.yml]

[softmattertheory]

Suggestion, @joshichaitanya3: Could you change the target of this PR to the morehessians branch? I've now fixed the race conditions—this was great we discovered them!—and so this test should work for that branch.

[joshichaitanya3]

Sure thing, I just did!