Revert "Revert "Refactor GetIMTIndex""

Originally reverted in order to revert
https://android-review.googlesource.com/#/c/244190/
but can now be merged again.

This reverts commit d4ceecc85a5aab2ec23ea1bd010692ba8c8aaa0c.

Test: m test-art-host

Change-Id: Id9205f2b77a378fc0f06088e78c66e81a49f712d
diff --git a/compiler/optimizing/code_generator_arm64.cc b/compiler/optimizing/code_generator_arm64.cc
index 07b7823..33eee3b 100644
--- a/compiler/optimizing/code_generator_arm64.cc
+++ b/compiler/optimizing/code_generator_arm64.cc
@@ -3561,7 +3561,7 @@
   __ Ldr(temp,
       MemOperand(temp, mirror::Class::ImtPtrOffset(kArm64PointerSize).Uint32Value()));
   uint32_t method_offset = static_cast<uint32_t>(ImTable::OffsetOfElement(
-      invoke->GetImtIndex() % ImTable::kSize, kArm64PointerSize));
+      invoke->GetImtIndex(), kArm64PointerSize));
   // temp = temp->GetImtEntryAt(method_offset);
   __ Ldr(temp, MemOperand(temp, method_offset));
   // lr = temp->GetEntryPoint();
@@ -5382,7 +5382,7 @@
            MemOperand(XRegisterFrom(locations->InAt(0)), method_offset));
   } else {
     uint32_t method_offset = static_cast<uint32_t>(ImTable::OffsetOfElement(
-        instruction->GetIndex() % ImTable::kSize, kArm64PointerSize));
+        instruction->GetIndex(), kArm64PointerSize));
     __ Ldr(XRegisterFrom(locations->Out()), MemOperand(XRegisterFrom(locations->InAt(0)),
         mirror::Class::ImtPtrOffset(kArm64PointerSize).Uint32Value()));
     __ Ldr(XRegisterFrom(locations->Out()),