Remove Assert(BgWriterShmem != NULL), which is rather pointless since

we'd dump core anyway immediately afterward if it were null; and it
seems to confuse some versions of icc into generating bad code.
Per report from Sergey Koposov.  Patched in HEAD only, for the moment,
since this is only likely to affect developers.

src/backend/postmaster/bgwriter.c

@@ -37,7 +37,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/postmaster/bgwriter.c,v 1.42 2007/09/11 17:15:33 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/postmaster/bgwriter.c,v 1.43 2007/09/16 16:33:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -189,7 +189,6 @@ BackgroundWriterMain(void)
 	sigjmp_buf	local_sigjmp_buf;
 	MemoryContext bgwriter_context;
 
-	Assert(BgWriterShmem != NULL);
 	BgWriterShmem->bgwriter_pid = MyProcPid;
 	am_bg_writer = true;
 
@@ -987,7 +986,6 @@ ForwardFsyncRequest(RelFileNode rnode, BlockNumber segno)
 
 	if (!IsUnderPostmaster)
 		return false;			/* probably shouldn't even get here */
-	Assert(BgWriterShmem != NULL);
 
 	LWLockAcquire(BgWriterCommLock, LW_EXCLUSIVE);
 	if (BgWriterShmem->bgwriter_pid == 0 ||