Clean up WaitLatch calls that passed latch without WL_LATCH_SET

The 'latch' argument is ignored if WL_LATCH_SET is not given. Clarify
these calls by not pointlessly passing MyLatch.

Discussion: https://www.postgresql.org/message-id/391abe21-413e-4d91-a650-b663af49500c@iki.fi

src/backend/libpq/be-secure-gssapi.c

@@ -450,7 +450,7 @@ read_or_wait(Port *port, ssize_t len)
 		 */
 		if (ret <= 0)
 		{
-			WaitLatchOrSocket(MyLatch,
+			WaitLatchOrSocket(NULL,
 							  WL_SOCKET_READABLE | WL_EXIT_ON_PM_DEATH,
 							  port->sock, 0, WAIT_EVENT_GSS_OPEN_SERVER);
 
@@ -668,7 +668,7 @@ secure_open_gssapi(Port *port)
 				/* Wait and retry if we couldn't write yet */
 				if (ret <= 0)
 				{
-					WaitLatchOrSocket(MyLatch,
+					WaitLatchOrSocket(NULL,
 									  WL_SOCKET_WRITEABLE | WL_EXIT_ON_PM_DEATH,
 									  port->sock, 0, WAIT_EVENT_GSS_OPEN_SERVER);
 					continue;

src/backend/libpq/be-secure-openssl.c

@@ -506,7 +506,7 @@ aloop:
 				else
 					waitfor = WL_SOCKET_WRITEABLE | WL_EXIT_ON_PM_DEATH;
 
-				(void) WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0,
+				(void) WaitLatchOrSocket(NULL, waitfor, port->sock, 0,
 										 WAIT_EVENT_SSL_OPEN_SERVER);
 				goto aloop;
 			case SSL_ERROR_SYSCALL:

src/backend/postmaster/walsummarizer.c

@@ -315,7 +315,7 @@ WalSummarizerMain(char *startup_data, size_t startup_data_len)
 		 * So a really fast retry time doesn't seem to be especially
 		 * beneficial, and it will clutter the logs.
 		 */
-		(void) WaitLatch(MyLatch,
+		(void) WaitLatch(NULL,
 						 WL_TIMEOUT | WL_EXIT_ON_PM_DEATH,
 						 10000,
 						 WAIT_EVENT_WAL_SUMMARIZER_ERROR);