Add runtime check for modulo by zero

[LT2H]

Checks for modulo and modulo-assignment by zero at runtime. Based on a suggestion in #1399.
Resolves #1399.

[hsutter]

Thanks!

[gregmarr]

@hsutter Did you intend to switch from importing std to including std when running the tests?

[hsutter]

@hsutter Did you intend to switch from importing std to including std when running the tests?

That's probably a good idea. @jarzec was maintaining and updating the test runner (thanks again!) -- do those use MSVC modules today which would have required that modules be built somehow (I vaguely recall seeing something like that)? If they do they should probably also switch to use -in to include std headers instead of importing the std module, which is what I did in this commit.

[jarzec]

@hsutter Did you intend to switch from importing std to including std when running the tests?

That's probably a good idea. @jarzec was maintaining and updating the test runner (thanks again!) -- do those use MSVC modules today which would have required that modules be built somehow (I vaguely recall seeing something like that)? If they do they should probably also switch to use -in to include std headers instead of importing the std module, which is what I did in this commit.

I have to admit I forgot the details, but clearly there was some effort at some stage to make import usable.
The tests were passing with imports (except the Windows runners where we have build issues, but that is a separate story).
I would indeed revert that particular change (not the whole PR) and switch back to imports.

@hsutter I will soon try open a quick PR readding imports. You can either merge it or close it.

First, however, I will update the regression tests to have a clean start.

EDIT
I have only just fully understood your response. I will update the tests shortly.

[jarzec]

Regression tests are fixed (among other changes) in #1442