Refactor GetIMTIndex

This allows us to more easily maintain and experiment with
interface method table indexing and hashing.

Change-Id: I719920fae7490dcedcda7c1c36db225c2b8b16df
diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index a8da5f2..135f0c4 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -2258,7 +2258,7 @@
       Address(temp, mirror::Class::ImtPtrOffset(kX86_64PointerSize).Uint32Value()));
   // temp = temp->GetImtEntryAt(method_offset);
   uint32_t method_offset = static_cast<uint32_t>(ImTable::OffsetOfElement(
-      invoke->GetImtIndex() % ImTable::kSize, kX86_64PointerSize));
+      invoke->GetImtIndex(), kX86_64PointerSize));
   // temp = temp->GetImtEntryAt(method_offset);
   __ movq(temp, Address(temp, method_offset));
   // call temp->GetEntryPoint();
@@ -3986,7 +3986,7 @@
             Address(locations->InAt(0).AsRegister<CpuRegister>(),
             mirror::Class::ImtPtrOffset(kX86_64PointerSize).Uint32Value()));
     method_offset = static_cast<uint32_t>(ImTable::OffsetOfElement(
-        instruction->GetIndex() % ImTable::kSize, kX86_64PointerSize));
+        instruction->GetIndex(), kX86_64PointerSize));
   }
   __ movq(locations->Out().AsRegister<CpuRegister>(),
           Address(locations->InAt(0).AsRegister<CpuRegister>(), method_offset));