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/compiler.h b/compiler/compiler.h
index 85abd66..b92bff6 100644
--- a/compiler/compiler.h
+++ b/compiler/compiler.h
@@ -18,7 +18,7 @@
 #define ART_COMPILER_COMPILER_H_
 
 #include "base/mutex.h"
-#include "dex_file.h"
+#include "dex/dex_file.h"
 #include "os.h"
 
 namespace art {