Selected_tests_gen should not generate non-jstest tasks. Currently, the logic it uses to exclude non-jstest tasks is only run on tasks generated by task_mappings (see here We should also run this logic on tasks generated by test_mappings. Currently, some tasks generated by test mappings are resulting in non-jstest tasks being generated (see example [here|https://evergreen.mongodb.com/version/5e6d148f2fbabe4bcd3215b5] which shows _concurrency* tasks being generated).

As a server engineer, I should know that selected_tests_gen only generates jstest tasks, to be in line with the scope of the Selected Tests project.

AC:

• Changing the files that are changed in the version above should not result in concurrency_* tasks being generated