Add some sanity checks in executor for query ID reporting

This commit adds three sanity checks in code paths of the executor where
it is possible to use hooks, checking that a query ID is reported in
pg_stat_activity if compute_query_id is enabled:
- ExecutorRun()
- ExecutorFinish()
- ExecutorEnd()

This causes the test in pg_stat_statements added in 933848d16dc9 to
complain immediately in ExecutorRun().  The idea behind this commit is
to help extensions to detect if they are missing query ID reports when a
query goes through the executor.  Perhaps this will prove to be a bad
idea, but let's see where this experience goes in v18 and newer
versions.

Reviewed-by: Sami Imseih
Discussion: https://postgr.es/m/ZuJb5xCKHH0A9tMN@paquier.xyz

src/backend/executor/execMain.c

@@ -50,6 +50,7 @@
 #include "foreign/fdwapi.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
+#include "nodes/queryjumble.h"
 #include "parser/parse_relation.h"
 #include "rewrite/rewriteHandler.h"
 #include "tcop/utility.h"
@@ -295,6 +296,9 @@ ExecutorRun(QueryDesc *queryDesc,
 			ScanDirection direction, uint64 count,
 			bool execute_once)
 {
+	/* If enabled, the query ID should be set. */
+	Assert(!IsQueryIdEnabled() || pgstat_get_my_query_id() != 0);
+
 	if (ExecutorRun_hook)
 		(*ExecutorRun_hook) (queryDesc, direction, count, execute_once);
 	else
@@ -403,6 +407,9 @@ standard_ExecutorRun(QueryDesc *queryDesc,
 void
 ExecutorFinish(QueryDesc *queryDesc)
 {
+	/* If enabled, the query ID should be set. */
+	Assert(!IsQueryIdEnabled() || pgstat_get_my_query_id() != 0);
+
 	if (ExecutorFinish_hook)
 		(*ExecutorFinish_hook) (queryDesc);
 	else
@@ -463,6 +470,9 @@ standard_ExecutorFinish(QueryDesc *queryDesc)
 void
 ExecutorEnd(QueryDesc *queryDesc)
 {
+	/* If enabled, the query ID should be set. */
+	Assert(!IsQueryIdEnabled() || pgstat_get_my_query_id() != 0);
+
 	if (ExecutorEnd_hook)
 		(*ExecutorEnd_hook) (queryDesc);
 	else