Update runtime to work with the OpenJdk String.

The key difference here is that the OpenJdk String class
does not maintain an offset or a count field into its backing
char[] array. The offset is assumed to be zero, and the count
is always array.length.

Change-Id: I8b0518642f440cd38d24d9b90c575b7110233cc5
diff --git a/compiler/image_writer.cc b/compiler/image_writer.cc
index 1b7ac06..1eedab8 100644
--- a/compiler/image_writer.cc
+++ b/compiler/image_writer.cc
@@ -604,7 +604,7 @@
     return;
   }
   mirror::String* string = obj->AsString();
-  const uint16_t* utf16_string = string->GetCharArray()->GetData() + string->GetOffset();
+  const uint16_t* utf16_string = string->GetCharArray()->GetData();
   ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
   ReaderMutexLock mu(Thread::Current(), *class_linker->DexLock());
   size_t dex_cache_count = class_linker->GetDexCacheCount();