dwrite: Remove unused code (Clang).

dlls/dwrite/bidi.c

@@ -513,12 +513,6 @@ static inline int get_prev_valid_char_from_run(IsolatedRun *run, int index)
     return index;
 }
 
-static inline int iso_previousChar(IsolatedRun *run, int index)
-{
-    if (index <= 0) return -1;
-    return index--;
-}
-
 static inline void iso_dump_types(const char* header, IsolatedRun *run)
 {
     int i, len = 0;

dlls/dwrite/shape.c

@@ -23,8 +23,6 @@
 
 #include "dwrite_private.h"
 
-WINE_DEFAULT_DEBUG_CHANNEL(dwrite);
-
 struct scriptshaping_cache
 {
     IDWriteFontFace *fontface;