Try to harden insert-conflict-specconflict against autovacuum.

Looks like guaibasaurus had a autovacuum running during the
controller_print_speculative_locks step (just added in
43e08419). Which does indeed seem quite possible.

Avoid the problem by only looking for the backends participating in
the test.

src/test/isolation/expected/insert-conflict-specconflict.out

@@ -361,7 +361,10 @@ s1: NOTICE:  acquiring advisory lock on 2
 step controller_print_speculative_locks: 
     SELECT pa.application_name, locktype, mode, granted
     FROM pg_locks pl JOIN pg_stat_activity pa USING (pid)
-    WHERE locktype IN ('speculative token', 'transactionid') AND pa.datname = current_database()
+    WHERE
+        locktype IN ('speculative token', 'transactionid')
+        AND pa.datname = current_database()
+        AND pa.application_name LIKE 'isolation/insert-conflict-specconflict-s%'
     ORDER BY 1, 2, 3, 4;
 
 application_namelocktype       mode           granted        
@@ -380,7 +383,10 @@ step s2_upsert: <... completed>
 step controller_print_speculative_locks: 
     SELECT pa.application_name, locktype, mode, granted
     FROM pg_locks pl JOIN pg_stat_activity pa USING (pid)
-    WHERE locktype IN ('speculative token', 'transactionid') AND pa.datname = current_database()
+    WHERE
+        locktype IN ('speculative token', 'transactionid')
+        AND pa.datname = current_database()
+        AND pa.application_name LIKE 'isolation/insert-conflict-specconflict-s%'
     ORDER BY 1, 2, 3, 4;
 
 application_namelocktype       mode           granted        
@@ -399,7 +405,10 @@ k1             inserted s2 with conflict update s1
 step controller_print_speculative_locks: 
     SELECT pa.application_name, locktype, mode, granted
     FROM pg_locks pl JOIN pg_stat_activity pa USING (pid)
-    WHERE locktype IN ('speculative token', 'transactionid') AND pa.datname = current_database()
+    WHERE
+        locktype IN ('speculative token', 'transactionid')
+        AND pa.datname = current_database()
+        AND pa.application_name LIKE 'isolation/insert-conflict-specconflict-s%'
     ORDER BY 1, 2, 3, 4;
 
 application_namelocktype       mode           granted        

src/test/isolation/specs/insert-conflict-specconflict.spec

@@ -63,7 +63,10 @@ step "controller_show_count" {SELECT COUNT(*) FROM upserttest; }
 step "controller_print_speculative_locks" {
     SELECT pa.application_name, locktype, mode, granted
     FROM pg_locks pl JOIN pg_stat_activity pa USING (pid)
-    WHERE locktype IN ('speculative token', 'transactionid') AND pa.datname = current_database()
+    WHERE
+        locktype IN ('speculative token', 'transactionid')
+        AND pa.datname = current_database()
+        AND pa.application_name LIKE 'isolation/insert-conflict-specconflict-s%'
     ORDER BY 1, 2, 3, 4;
 }