Fix collation for postgres for unit tests (#7359)

When running the UTs against a postgres deatbase, we need to set the collation
correctly.

changelog.d/7359.misc

@@ -0,0 +1 @@
+Fix collation for postgres for unit tests.

tests/utils.py

@@ -74,7 +74,10 @@ def setupdb():
         db_conn.autocommit = True
         cur = db_conn.cursor()
         cur.execute("DROP DATABASE IF EXISTS %s;" % (POSTGRES_BASE_DB,))
-        cur.execute("CREATE DATABASE %s;" % (POSTGRES_BASE_DB,))
+        cur.execute(
+            "CREATE DATABASE %s ENCODING 'UTF8' LC_COLLATE='C' LC_CTYPE='C' "
+            "template=template0;" % (POSTGRES_BASE_DB,)
+        )
         cur.close()
         db_conn.close()