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/compiler/utils/atomic_dex_ref_map.h b/compiler/utils/atomic_dex_ref_map.h
index 205543f..9ff506d 100644
--- a/compiler/utils/atomic_dex_ref_map.h
+++ b/compiler/utils/atomic_dex_ref_map.h
@@ -18,7 +18,7 @@
 #define ART_COMPILER_UTILS_ATOMIC_DEX_REF_MAP_H_
 
 #include "base/dchecked_vector.h"
-#include "dex_file_reference.h"
+#include "dex/dex_file_reference.h"
 #include "safe_map.h"
 
 namespace art {