Revise sinval code to remove no-longer-used tuple TID from inval messages.

This requires adjusting the API for syscache callback functions: they now
get a hash value, not a TID, to identify the target tuple.  Most of them
weren't paying any attention to that argument anyway, but plancache did
require a small amount of fixing.

Also, improve performance a trifle by avoiding sending duplicate inval
messages when a heap_update isn't changing the catcache lookup columns.

src/backend/utils/cache/ts_cache.c

@@ -90,7 +90,7 @@ static Oid	TSCurrentConfigCache = InvalidOid;
  * table address as the "arg".
  */
 static void
-InvalidateTSCacheCallBack(Datum arg, int cacheid, ItemPointer tuplePtr)
+InvalidateTSCacheCallBack(Datum arg, int cacheid, uint32 hashvalue)
 {
 	HTAB	   *hash = (HTAB *) DatumGetPointer(arg);
 	HASH_SEQ_STATUS status;