Change authorization set serialization approach to ensure that 32 vs 64
bit size and alignment differences don't cause problems.

Change-Id: I4a308cfac782161db2f1456adb2d6a56537e61f1
diff --git a/google_keymaster_test.cpp b/google_keymaster_test.cpp
index 435257c..1a53172 100644
--- a/google_keymaster_test.cpp
+++ b/google_keymaster_test.cpp
@@ -194,8 +194,8 @@
 
     ASSERT_EQ(KM_ERROR_OK, rsp.error);
     EXPECT_EQ(0U, rsp.enforced.size());
-    EXPECT_EQ(8U, rsp.enforced.SerializedSize());
-    EXPECT_GT(rsp.unenforced.SerializedSize(), 8U);
+    EXPECT_EQ(12U, rsp.enforced.SerializedSize());
+    EXPECT_GT(rsp.unenforced.SerializedSize(), 12U);
 
     // Check specified tags are all present in unenforced characteristics
     EXPECT_TRUE(contains(rsp.unenforced, TAG_PURPOSE, KM_PURPOSE_SIGN));