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/test/common/stack_inspect.cc b/test/common/stack_inspect.cc
index 046b1fb..fd62737 100644
--- a/test/common/stack_inspect.cc
+++ b/test/common/stack_inspect.cc
@@ -19,7 +19,7 @@
 #include <android-base/logging.h>
 
 #include "base/mutex.h"
-#include "dex_file-inl.h"
+#include "dex/dex_file-inl.h"
 #include "jni_internal.h"
 #include "mirror/class-inl.h"
 #include "nth_caller_visitor.h"