Revert "Avoid creating archive status ".ready" files too early"

This reverts commit 515e3d84a0b5 and equivalent commits in back
branches.  This solution to the problem has a number of problems, so
we'll try again with a different approach.

Per note from Andres Freund

Discussion: https://postgr.es/m/20210831042949.52eqp5xwbxgrfank@alap3.anarazel.de

src/backend/postmaster/walwriter.c

@@ -248,13 +248,6 @@ WalWriterMain(void)
 		/* Process any signals received recently */
 		HandleWalWriterInterrupts();
 
-		/*
-		 * Notify the archiver of any WAL segments that are ready.  We do this
-		 * here to handle a race condition where WAL is flushed to disk prior
-		 * to registering the segment boundary.
-		 */
-		NotifySegmentsReadyForArchive(GetFlushRecPtr());
-
 		/*
 		 * Do what we're here for; then, if XLogBackgroundFlush() found useful
 		 * work to do, reset hibernation counter.

src/include/access/xlog.h

@@ -349,7 +349,6 @@ extern XLogRecPtr GetInsertRecPtr(void);
 extern XLogRecPtr GetFlushRecPtr(void);
 extern XLogRecPtr GetLastImportantRecPtr(void);
 extern void RemovePromoteSignalFiles(void);
-extern void NotifySegmentsReadyForArchive(XLogRecPtr flushRecPtr);
 
 extern bool PromoteIsTriggered(void);
 extern bool CheckPromoteSignal(void);

src/include/access/xlogdefs.h

@@ -46,7 +46,6 @@ typedef uint64 XLogRecPtr;
  * XLogSegNo - physical log file sequence number.
  */
 typedef uint64 XLogSegNo;
-#define MaxXLogSegNo	((XLogSegNo) 0xFFFFFFFFFFFFFFFF)
 
 /*
  * TimeLineID (TLI) - identifies different database histories to prevent