Add code item accessor helper classes

Add classes to abstract accesses to code item data. These classes
handle both standard dex and compact dex.

Added:
- CodeItemInstructionsAccessor to handle code item instructions.
- CodeItemDataAccessor to handle code item data excluding debug info.

Moved inline_method_analyzer to use the new classes to test the new
APIs.

Bug: 63756964
Test: test-art-host
Change-Id: I9926acb77b81fa64ed4a3b49b7bed1aab30a0f33
diff --git a/dex2oat/dex2oat_test.cc b/dex2oat/dex2oat_test.cc
index afca26d..c2556aa 100644
--- a/dex2oat/dex2oat_test.cc
+++ b/dex2oat/dex2oat_test.cc
@@ -941,7 +941,7 @@
                class_it.Next()) {
             if (class_it.IsAtMethod() && class_it.GetMethodCodeItem() != nullptr) {
               for (const DexInstructionPcPair& inst :
-                  class_it.GetMethodCodeItem()->Instructions()) {
+                       class_it.GetMethodCodeItem()->Instructions()) {
                 ASSERT_FALSE(inst->IsQuickened());
               }
             }