Add tests for Thumb2RelativePatcher.

Also make the thumb2/arm64 thunk allocation precise instead
of eagerly allocating thunk space. This allows the calls to
use the maximum positive offset.

Change-Id: Ifa95b0bb00bd73eeab0c2905d21e2f3078f4b0a8
diff --git a/build/Android.gtest.mk b/build/Android.gtest.mk
index 58a3290..f834a38 100644
--- a/build/Android.gtest.mk
+++ b/build/Android.gtest.mk
@@ -193,6 +193,7 @@
   compiler/elf_writer_test.cc \
   compiler/image_test.cc \
   compiler/jni/jni_compiler_test.cc \
+  compiler/linker/arm/relative_patcher_thumb2_test.cc \
   compiler/linker/x86/relative_patcher_x86_test.cc \
   compiler/linker/x86_64/relative_patcher_x86_64_test.cc \
   compiler/oat_test.cc \