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/openjdkjvmti/fixed_up_dex_file.h b/openjdkjvmti/fixed_up_dex_file.h
index 4cb39cf..b8f349c 100644
--- a/openjdkjvmti/fixed_up_dex_file.h
+++ b/openjdkjvmti/fixed_up_dex_file.h
@@ -39,7 +39,7 @@
 #include "jvmti.h"
 
 #include "base/mutex.h"
-#include "dex_file.h"
+#include "dex/dex_file.h"
 
 namespace openjdkjvmti {