tests/stress: Improve qstr_limit test to run on minimal targets.

Changes here are:
- Split out string format module sub-test to a separate test file, so it
  can be skipped on targets that don't have str% capabilities.
- Print the whole type instead of `.__name__` to support targets that don't
  have `.__name__` enabled (this still tests the same thing).
- Print `RuntimeError` exception message to be sure the correct exception
  is being raised.

This test now runs on unix and zephyr minimal configurations.

Signed-off-by: Damien George <damien@micropython.org>

0 files changed, 0 insertions, 0 deletions