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/optimizing/code_generator_mips.h b/compiler/optimizing/code_generator_mips.h
index cf8e7a3..32b3e42 100644
--- a/compiler/optimizing/code_generator_mips.h
+++ b/compiler/optimizing/code_generator_mips.h
@@ -18,7 +18,7 @@
 #define ART_COMPILER_OPTIMIZING_CODE_GENERATOR_MIPS_H_
 
 #include "code_generator.h"
-#include "dex_file_types.h"
+#include "dex/dex_file_types.h"
 #include "driver/compiler_options.h"
 #include "nodes.h"
 #include "parallel_move_resolver.h"