Revert "[refer #PGPRO-6612] Count max procs"

We deliberately don't include max_prepared_xact and needn't include
MaxATX either.  We iterate over ProcGlobal->allProcCount which doesn't
include them.

This reverts commit df1aa39.

Author: Sergey Shinderuk

Diff for: pg_wait_sampling.c

@@ -113,10 +113,6 @@ get_max_procs_count(void)
 	count += MaxConnections + autovacuum_max_workers + 1
 			+ max_worker_processes;
 
-#if PG_VERSION_NUM >= 140000 && defined(PGPRO_EE)
-	count += MaxATX;
-#endif
-
 	/*
 	 * Starting with pg12, wal senders aren't part of MaxConnections anymore
 	 * and have to be accounted for.