Pass arguments to test binary from flit make

[jjgarzella]

Feature Request

Describe the new feature:
Right now, if I run flit make, it runs each test in its default configuration, running all precisions and timing tests. However, for certain cases (e.g. preliminary tests), I would like to only run a single precision, and not have to use timing tests. Currently, I have to do this manually.

Suggested change:
Add an option similar to --make-args, possibly called --test-args, which forwards arguments to the test binaries.

Alternative approaches:
Doing it manually is a workaround, but it takes a little time to figure out how to do it right.

[mikebentley15]

If you do not want to run with timing, you can turn off the timing in flit-config.toml. As for which precisions to run and such, I think it would be good to give a flag. I would probably add similar flags to flit make that the test executables have, such as --precision and others. For the implementation within the Makefile, I think we can make use of environment variables or Make variables to communicate this intent.

Thanks for this feedback JJ