Tidy up from frontend Assert change.

Quiet compiler warnings noted by Peter Eisentraut.

Author: adunstan

src/backend/utils/mb/encnames.c

@@ -6,7 +6,6 @@
  */
 #ifdef FRONTEND
 #include "postgres_fe.h"
-#define Assert(condition)
 #else
 #include "postgres.h"
 #include "utils/builtins.h"

src/backend/utils/mb/wchar.c

@@ -7,7 +7,6 @@
 /* can be used in either frontend or backend */
 #ifdef FRONTEND
 #include "postgres_fe.h"
-#define Assert(condition)
 #else
 #include "postgres.h"
 #endif