Fixed bug in auth token formatting.

This patch also adds test for the functions hidlVec2AuthToken
and authToken2HidlVec.

Test: /data/nativetest64/keystore_unit_tests/keystore_unit_tests
Change-Id: I823939a62ca94efa45509c89d1013ec87f51d04c
diff --git a/keystore/tests/Android.bp b/keystore/tests/Android.bp
index 5718b73..6d8f75d 100644
--- a/keystore/tests/Android.bp
+++ b/keystore/tests/Android.bp
@@ -6,7 +6,11 @@
         "-Werror",
         "-Wextra",
     ],
-    srcs: ["auth_token_table_test.cpp"],
+    srcs: [
+        "auth_token_table_test.cpp",
+        "auth_token_formatting_test.cpp",
+        "gtest_main.cpp",
+    ],
     name: "keystore_unit_tests",
     tags: ["test"],
     static_libs: [