Creates the test.xml report file at the end, rather than stream-write it across test methods. This is a roll-forward of cl/208220646.
Creates the test.xml report file at the end, rather than stream-write it across test methods. This is a roll-forward of cl/208220646.

PiperOrigin-RevId: 209784505

abseil/abseil-py,abseil/abseil-py