QtTest/generate_expected_output.py: Add TeamCity logging format.

Adapt the script to generate output for the new TeamCity format
added by fbd6acedac.

Change-Id: I9435382ec3daf80428c324c58434aa951841bf08
Reviewed-by: Borgar Øvsthus <borgar.ovsthus@fmcti.com>
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@theqtcompany.com>

tests/auto/testlib/selftests/generate_expected_output.py

@@ -34,7 +34,7 @@ import sys
 import subprocess
 import re
 
-formats = ['xml', 'txt', 'xunitxml', 'lightxml']
+formats = ['xml', 'txt', 'xunitxml', 'lightxml', 'teamcity']
 
 qtver = subprocess.check_output(['qmake', '-query', 'QT_VERSION']).strip().decode('utf-8')
 rootPath = os.getcwd()