& everything builds in the correct manner.
- `make check-stage1-std NO_REBUILD=1` - test the standard library without
rebuilding the entire compiler
-- `make check TESTNAME=<substring-of-test-name>` - Run a single test file
+- `make check TESTNAME=<substring-of-test-name>` - Run a matching set of tests.
- `TESTNAME` should be a substring of the tests to match against e.g. it could
be the fully qualified test name, or just a part of it.
`TESTNAME=collections::hash::map::test_map::test_capacity_not_less_than_len`