Move dexCacheStrings from ArtMethod to Class

Adds one load for const strings which are not direct.

Saves >= 60KB of memory avg per app.
Image size: -350KB.

Bug: 17643507
Change-Id: I2d1a3253d9de09682be9bc6b420a29513d592cc8

(cherry picked from commit f521f423b66e952f746885dd9f6cf8ef2788955d)
diff --git a/compiler/optimizing/code_generator_x86.cc b/compiler/optimizing/code_generator_x86.cc
index 917b7dd..3689452 100644
--- a/compiler/optimizing/code_generator_x86.cc
+++ b/compiler/optimizing/code_generator_x86.cc
@@ -3306,7 +3306,8 @@
 
   Register out = load->GetLocations()->Out().As<Register>();
   codegen_->LoadCurrentMethod(out);
-  __ movl(out, Address(out, mirror::ArtMethod::DexCacheStringsOffset().Int32Value()));
+  __ movl(out, Address(out, mirror::ArtMethod::DeclaringClassOffset().Int32Value()));
+  __ movl(out, Address(out, mirror::Class::DexCacheStringsOffset().Int32Value()));
   __ movl(out, Address(out, CodeGenerator::GetCacheOffset(load->GetStringIndex())));
   __ testl(out, out);
   __ j(kEqual, slow_path->GetEntryLabel());