Use variable encoding for StackMap.

dex_pc, native_pc_offset, dex_register_map_offset, inline_info_offset,
and register_mask can now be encoded in 1, 2, 3, or 4 bytes.

Change-Id: I15f93e8226ce374204d44c5a80a9fd89bda2687c
diff --git a/compiler/optimizing/stack_map_test.cc b/compiler/optimizing/stack_map_test.cc
index b9bf016..8d160bc 100644
--- a/compiler/optimizing/stack_map_test.cc
+++ b/compiler/optimizing/stack_map_test.cc
@@ -401,9 +401,8 @@
   // ...the offset of the second Dex register map (relative to the
   // beginning of the Dex register maps region) is 255 (i.e.,
   // kNoDexRegisterMapSmallEncoding).
-  ASSERT_NE(StackMap::kNoDexRegisterMap, stack_map1.GetDexRegisterMapOffset(code_info));
-  ASSERT_EQ(StackMap::kNoDexRegisterMapSmallEncoding,
-            stack_map1.GetDexRegisterMapOffset(code_info));
+  ASSERT_NE(stack_map1.GetDexRegisterMapOffset(code_info), StackMap::kNoDexRegisterMap);
+  ASSERT_EQ(stack_map1.GetDexRegisterMapOffset(code_info), 0xFFu);
 }
 
 TEST(StackMapTest, TestShareDexRegisterMap) {