Helper SQL: Explicitly include QUERY_CANCELED in exception catching

Per the Postgres documentation at https://www.postgresql.org/docs/current/plpgsql-control-structures.html#PLPGSQL-ERROR-TRAPPING
"The special condition name OTHERS matches every error type except
QUERY_CANCELED and ASSERT_FAILURE.", thus we need to explicitly include
the QUERY_CANCELED in order to deallocate the statement in case of
statement timeouts. Since we don't use asserts, we do not need to catch
ASSERT_FAILURE.

util/explain_analyze_helper.sql

@@ -35,7 +35,7 @@ BEGIN
   EXECUTE 'PREPARE pganalyze_explain_analyze ' || param_types_str || ' AS ' || prepared_query;
   BEGIN
     EXECUTE explain_prefix || 'EXECUTE pganalyze_explain_analyze' || params_str INTO STRICT result;
-  EXCEPTION WHEN OTHERS THEN
+  EXCEPTION WHEN QUERY_CANCELED OR OTHERS THEN
     DEALLOCATE pganalyze_explain_analyze;
     RAISE;
   END;