Use MyBackendType in more places to check what process this is

Remove IsBackgroundWorker, IsAutoVacuumLauncherProcess(),
IsAutoVacuumWorkerProcess(), and IsLogicalSlotSyncWorker() in favor of
new Am*Process() macros that use MyBackendType. For consistency with
the existing Am*Process() macros.

Reviewed-by: Andres Freund
Discussion: https://www.postgresql.org/message-id/f3ecd4cb-85ee-4e54-8278-5fabfb3a4ed0@iki.fi

src/backend/replication/logical/slotsync.c

@@ -113,9 +113,6 @@ static long sleep_ms = MIN_SLOTSYNC_WORKER_NAPTIME_MS;
 /* The restart interval for slot sync work used by postmaster */
 #define SLOTSYNC_RESTART_INTERVAL_SEC 10
 
-/* Flag to tell if we are in a slot sync worker process */
-static bool am_slotsync_worker = false;
-
 /*
  * Flag to tell if we are syncing replication slots. Unlike the 'syncing' flag
  * in SlotSyncCtxStruct, this flag is true only if the current process is
@@ -491,7 +488,7 @@ synchronize_one_slot(RemoteSlot *remote_slot, Oid remote_dbid)
 	latestFlushPtr = GetStandbyFlushRecPtr(NULL);
 	if (remote_slot->confirmed_lsn > latestFlushPtr)
 	{
-		ereport(am_slotsync_worker ? LOG : ERROR,
+		ereport(AmLogicalSlotSyncWorkerProcess() ? LOG : ERROR,
 				errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				errmsg("skipping slot synchronization as the received slot sync"
 					   " LSN %X/%X for slot \"%s\" is ahead of the standby position %X/%X",
@@ -1114,8 +1111,6 @@ ReplSlotSyncWorkerMain(int argc, char *argv[])
 	sigjmp_buf	local_sigjmp_buf;
 	StringInfoData app_name;
 
-	am_slotsync_worker = true;
-
 	MyBackendType = B_SLOTSYNC_WORKER;
 
 	init_ps_display(NULL);
@@ -1438,15 +1433,6 @@ IsSyncingReplicationSlots(void)
 	return syncing_slots;
 }
 
-/*
- * Is current process a slot sync worker?
- */
-bool
-IsLogicalSlotSyncWorker(void)
-{
-	return am_slotsync_worker;
-}
-
 /*
  * Amount of shared memory required for slot synchronization.
  */