Python: Remove one more unnecessary taint test

Author: RasmusWL

python/ql/test/experimental/dataflow/model-summaries/model_summaries.py

@@ -44,8 +44,6 @@ def SINK_F(x):
 not_via_lambda = MS_apply_lambda(lambda x: 1, SOURCE)
 SINK_F(not_via_lambda)
 
-untainted_lambda = MS_apply_lambda(lambda x: 1, TAINTED_STRING)
-ensure_not_tainted(untainted_lambda)
 
 # Collection summaries
 via_reversed = MS_reversed([SOURCE])