Revert "Refactor GetIMTIndex"

I need to revert this to get https://android-review.googlesource.com/#/c/244190/ to cleanly revert. Matthew, do you mind rewriting it?

This reverts commit 50706437d8216e41f0fea1e413cda7891324d397.

Change-Id: I5c1435f5dffb46dbb5b613b22adb88c7770304f2
diff --git a/runtime/entrypoints/entrypoint_utils-inl.h b/runtime/entrypoints/entrypoint_utils-inl.h
index db3f88f..916ca29 100644
--- a/runtime/entrypoints/entrypoint_utils-inl.h
+++ b/runtime/entrypoints/entrypoint_utils-inl.h
@@ -19,7 +19,7 @@
 
 #include "entrypoint_utils.h"
 
-#include "art_method-inl.h"
+#include "art_method.h"
 #include "class_linker-inl.h"
 #include "common_throws.h"
 #include "dex_file.h"
@@ -559,7 +559,7 @@
       }
     }
     case kInterface: {
-      uint32_t imt_index = resolved_method->GetImtIndex();
+      uint32_t imt_index = resolved_method->GetDexMethodIndex() % ImTable::kSize;
       size_t pointer_size = class_linker->GetImagePointerSize();
       ArtMethod* imt_method = (*this_object)->GetClass()->GetImt(pointer_size)->
           Get(imt_index, pointer_size);