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/exception_test.cc b/compiler/exception_test.cc
index 59d20f8..8f7ab05 100644
--- a/compiler/exception_test.cc
+++ b/compiler/exception_test.cc
@@ -20,11 +20,11 @@
 #include "base/callee_save_type.h"
 #include "base/enums.h"
 #include "class_linker.h"
-#include "code_item_accessors-inl.h"
 #include "common_runtime_test.h"
-#include "dex_file-inl.h"
-#include "dex_file.h"
-#include "dex_file_exception_helpers.h"
+#include "dex/code_item_accessors-inl.h"
+#include "dex/dex_file-inl.h"
+#include "dex/dex_file.h"
+#include "dex/dex_file_exception_helpers.h"
 #include "gtest/gtest.h"
 #include "handle_scope-inl.h"
 #include "leb128.h"