Add tests for SEA IR types infrastructure.

type_data_test.cc: Tests the type store used to record info on
                the types of results from instructions.
type_inferecen_visitor_test.cc: Tests type merging and related
                operations.
Android.gtest.mk: Included new tests.
type_inference_visitor.h/.cc: Marked function as const
                and made public.
scoped_hashtable_test.cc: Included full header path in #include.

Change-Id: I868461dcaed1e7f75db15958b83a3db7e17f6a64
diff --git a/build/Android.gtest.mk b/build/Android.gtest.mk
index e069d88..4d1e18d 100644
--- a/build/Android.gtest.mk
+++ b/build/Android.gtest.mk
@@ -60,7 +60,9 @@
 
 ifeq ($(ART_SEA_IR_MODE),true)
 TEST_COMMON_SRC_FILES += \
-	compiler/utils/scoped_hashtable_test.cc
+	compiler/utils/scoped_hashtable_test.cc \
+	compiler/sea_ir/types/type_data_test.cc \
+	compiler/sea_ir/types/type_inference_visitor_test.cc
 endif
 
 TEST_TARGET_SRC_FILES := \