Allow instructors to select a subset of test groups to run

[donny-wong]

Context:
There are times when an instructor/TA may just want to run a subset of test groups for one or all submissions of an assignment, but at the moment they do not have that option. They would need to run all test groups again for each “Run Tests”.

Proposed solution:
When the “Run Tests” button is selected for either for an individual test run (within an individual submission->Test Results Tab), or Mass selection of submissions test run (from the submissions table -> “Run Tests” button above the submissions table), a modal pops up with a list of Test Groups with a checkbox next to each of them. A select all check box is at the top. Perhaps by default to have them all checked, and when the instructor/TA only wants to run a subset of them, they can have the choice to only select the ones they want in that test run.