Remove unused wait events.

Commit 46482432 introduced the wait events which were neither used by
that commit nor by follow-up commits for that work.

Author: Masahiro Ikeda
Backpatch-through: 14, where it was introduced
Discussion: https://postgr.es/m/ff077840-3ab2-04dd-bbe4-4f5dfd2ad481@oss.nttdata.com

doc/src/sgml/monitoring.sgml

@@ -1549,22 +1549,6 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
       <entry><literal>WALWrite</literal></entry>
       <entry>Waiting for a write to a WAL file.</entry>
      </row>
-     <row>
-      <entry><literal>LogicalChangesRead</literal></entry>
-      <entry>Waiting for a read from a logical changes file.</entry>
-     </row>
-     <row>
-      <entry><literal>LogicalChangesWrite</literal></entry>
-      <entry>Waiting for a write to a logical changes file.</entry>
-     </row>
-     <row>
-      <entry><literal>LogicalSubxactRead</literal></entry>
-      <entry>Waiting for a read from a logical subxact file.</entry>
-     </row>
-     <row>
-      <entry><literal>LogicalSubxactWrite</literal></entry>
-      <entry>Waiting for a write to a logical subxact file.</entry>
-     </row>
     </tbody>
    </tgroup>
   </table>

src/backend/utils/activity/wait_event.c

@@ -714,18 +714,6 @@ pgstat_get_wait_io(WaitEventIO w)
 		case WAIT_EVENT_WAL_WRITE:
 			event_name = "WALWrite";
 			break;
-		case WAIT_EVENT_LOGICAL_CHANGES_READ:
-			event_name = "LogicalChangesRead";
-			break;
-		case WAIT_EVENT_LOGICAL_CHANGES_WRITE:
-			event_name = "LogicalChangesWrite";
-			break;
-		case WAIT_EVENT_LOGICAL_SUBXACT_READ:
-			event_name = "LogicalSubxactRead";
-			break;
-		case WAIT_EVENT_LOGICAL_SUBXACT_WRITE:
-			event_name = "LogicalSubxactWrite";
-			break;
 
 			/* no default case, so that compiler will warn */
 	}

src/include/utils/wait_event.h

@@ -220,11 +220,7 @@ typedef enum
 	WAIT_EVENT_WAL_READ,
 	WAIT_EVENT_WAL_SYNC,
 	WAIT_EVENT_WAL_SYNC_METHOD_ASSIGN,
-	WAIT_EVENT_WAL_WRITE,
-	WAIT_EVENT_LOGICAL_CHANGES_READ,
-	WAIT_EVENT_LOGICAL_CHANGES_WRITE,
-	WAIT_EVENT_LOGICAL_SUBXACT_READ,
-	WAIT_EVENT_LOGICAL_SUBXACT_WRITE
+	WAIT_EVENT_WAL_WRITE
 } WaitEventIO;