Python: TaintTracking: Move tests of py3 string methods

python/ql/test/experimental/dataflow/tainttracking/string/test.py

@@ -49,7 +49,6 @@ def str_methods():
     tb = TAINTED_BYTES
     ensure_tainted(
         ts.capitalize(),
-        ts.casefold(),
         ts.center(100),
         ts.expandtabs(),
 
@@ -57,9 +56,6 @@ def str_methods():
         "{}".format(ts),
         "{unsafe}".format(unsafe=ts),
 
-        ts.format_map({}),
-        "{unsafe}".format_map({"unsafe": ts}),
-
         ts.join(["", ""]),
         "".join([ts]),