Create dex subdirectory

Move all the DexFile related source to a common subdirectory dex/ of
runtime.

Bug: 71361973
Test: make -j 50 test-art-host
Change-Id: I59e984ed660b93e0776556308be3d653722f5223
diff --git a/dex2oat/dex2oat_options.h b/dex2oat/dex2oat_options.h
index f8198ee..ccc85c8 100644
--- a/dex2oat/dex2oat_options.h
+++ b/dex2oat/dex2oat_options.h
@@ -22,9 +22,9 @@
 #include <vector>
 
 #include "base/variant_map.h"
-#include "cdex/compact_dex_level.h"
 #include "cmdline_types.h"  // TODO: don't need to include this file here
 #include "compiler.h"
+#include "dex/compact_dex_level.h"
 #include "driver/compiler_options_map.h"
 #include "image.h"