Use pg_ctl promote -w in TAP tests

Switch TAP tests to use the new wait mode of pg_ctl promote.  This
allows avoiding extra logic with poll_query_until() to be sure that a
promoted standby is ready for read-write queries.

From: Michael Paquier <michael.paquier@gmail.com>

src/bin/pg_rewind/RewindTest.pm

@@ -161,12 +161,8 @@ sub promote_standby
 	  or die "Timed out while waiting for standby to receive and write WAL";
 
 	# Now promote slave and insert some new data on master, this will put
-	# the master out-of-sync with the standby. Wait until the standby is
-	# out of recovery mode, and is ready to accept read-write connections.
+	# the master out-of-sync with the standby.
 	$node_standby->promote;
-	$node_standby->poll_query_until('postgres',
-		"SELECT NOT pg_is_in_recovery()")
-	  or die "Timed out while waiting for promotion of standby";
 
 	# Force a checkpoint after the promotion. pg_rewind looks at the control
 	# file to determine what timeline the server is on, and that isn't updated

src/test/perl/PostgresNode.pm

@@ -723,7 +723,7 @@ sub restart
 
 =item $node->promote()
 
-Wrapper for pg_ctl promote
+Wrapper for pg_ctl promote -w
 
 =cut
 
@@ -735,7 +735,8 @@ sub promote
 	my $logfile = $self->logfile;
 	my $name    = $self->name;
 	print "### Promoting node \"$name\"\n";
-	TestLib::system_log('pg_ctl', '-D', $pgdata, '-l', $logfile, 'promote');
+	TestLib::system_log('pg_ctl', '-D', $pgdata, '-w', '-l', $logfile,
+		'promote');
 }
 
 # Internal routine to enable streaming replication on a standby node.

src/test/recovery/t/004_timeline_switch.pl

@@ -57,10 +57,7 @@ recovery_target_timeline='latest'
 $node_standby_2->restart;
 
 # Insert some data in standby 1 and check its presence in standby 2
-# to ensure that the timeline switch has been done. Standby 1 needs
-# to exit recovery first before moving on with the test.
-$node_standby_1->poll_query_until('postgres',
-	"SELECT pg_is_in_recovery() <> true");
+# to ensure that the timeline switch has been done.
 $node_standby_1->safe_psql('postgres',
 	"INSERT INTO tab_int VALUES (generate_series(1001,2000))");
 $until_lsn = $node_standby_1->safe_psql('postgres',