Unable to capture xsim output on test failure

[xmos-jmccarthy]

When a test fails there does not appear to be a way to get the xsim output. This is extremely useful when trying to debug new tests.

It appears that capturing the output of the pytest call allows you to look at output if capfd.disabled() is set when calling run_with_pyxsim as a temporary workaround.

pytest 2>&1 | tee text.txt