bdd: run full import on tests

This uncovered a couple of outdated/wrong tests which have been
fixed, too.

test/bdd/steps/table_compare.py

@@ -62,11 +62,14 @@ class NominatimID:
                     ','.join(['*'] + (extra_columns or [])), table)
         cur.execute(query, (pid, ))
 
-    def get_place_id(self, cur):
+    def get_place_id(self, cur, allow_empty=False):
         """ Look up the place id for the ID. Throws an assertion if the ID
             is not unique.
         """
         self.query_osm_id(cur, "SELECT place_id FROM placex WHERE {}")
+        if cur.rowcount == 0 and allow_empty:
+            return None
+
         assert cur.rowcount == 1, \
                "Place ID {!s} not unique. Found {} entries.".format(self, cur.rowcount)