Fix Copy-Paste error.

Author: Cornelius Riemenschneider

testing/acceptance_test.py

@@ -903,7 +903,7 @@ def test(self, i):
         test_a_workers_and_test_count = get_workers_and_test_count_by_prefix(
             'test_a.py::TestA', result.outlines)
         test_b_workers_and_test_count = get_workers_and_test_count_by_prefix(
-            'test_b.py::TestB', result.outlines)
+            'test_a.py::TestB', result.outlines)
 
         assert test_a_workers_and_test_count in ({'gw0': 10}, {'gw1': 0}) or \
             test_a_workers_and_test_count in ({'gw0': 0}, {'gw1': 10})