Remove assertion checking query ID in execMain.c

This assertion has been added by 24f5205948, but Alexander Lakhin has
proved that the ExecutorRun() one can be broken by using a PL function
that manipulates compute_query_id and track_activities, while the ones
in ExecutorFinish() and ExecutorEnd() could be triggered when cleaning
up portals at the beginning of a new query execution.

Discussion: https://postgr.es/m/b37d8e6c-e83d-e157-8865-1b2460a6aef2@gmail.com

src/backend/executor/execMain.c

@@ -71,18 +71,6 @@ ExecutorEnd_hook_type ExecutorEnd_hook = NULL;
 /* Hook for plugin to get control in ExecCheckPermissions() */
 ExecutorCheckPerms_hook_type ExecutorCheckPerms_hook = NULL;
 
-/*
- * Check that the query ID is set, which is something that happens only
- * if compute_query_id is enabled (or a module forced it), if track_activities
- * is enabled, and if a client provided a query string to map with the query
- * ID computed from it.
- */
-#define EXEC_CHECK_QUERY_ID \
-do { \
-	Assert(!IsQueryIdEnabled() || !pgstat_track_activities ||		\
-		   !debug_query_string || pgstat_get_my_query_id() != 0);	\
-} while(0)
-
 /* decls for local routines only used within this module */
 static void InitPlan(QueryDesc *queryDesc, int eflags);
 static void CheckValidRowMarkRel(Relation rel, RowMarkType markType);
@@ -308,9 +296,6 @@ ExecutorRun(QueryDesc *queryDesc,
 			ScanDirection direction, uint64 count,
 			bool execute_once)
 {
-	/* If enabled, the query ID should be set. */
-	EXEC_CHECK_QUERY_ID;
-
 	if (ExecutorRun_hook)
 		(*ExecutorRun_hook) (queryDesc, direction, count, execute_once);
 	else
@@ -419,9 +404,6 @@ standard_ExecutorRun(QueryDesc *queryDesc,
 void
 ExecutorFinish(QueryDesc *queryDesc)
 {
-	/* If enabled, the query ID should be set. */
-	EXEC_CHECK_QUERY_ID;
-
 	if (ExecutorFinish_hook)
 		(*ExecutorFinish_hook) (queryDesc);
 	else
@@ -482,9 +464,6 @@ standard_ExecutorFinish(QueryDesc *queryDesc)
 void
 ExecutorEnd(QueryDesc *queryDesc)
 {
-	/* If enabled, the query ID should be set. */
-	EXEC_CHECK_QUERY_ID;
-
 	if (ExecutorEnd_hook)
 		(*ExecutorEnd_hook) (queryDesc);
 	else