binderUnitTests: getOpenAshmemSize

In preparation for changing the implementation of this API, it has no
tests!

Bug: 195752513
Test: binderUnitTest
Change-Id: I4207f636b61dabbc81c5e188aa5cde0d5d1ba6ee
diff --git a/libs/binder/tests/Android.bp b/libs/binder/tests/Android.bp
index 680f0ed..86da588 100644
--- a/libs/binder/tests/Android.bp
+++ b/libs/binder/tests/Android.bp
@@ -87,6 +87,7 @@
     srcs: ["binderParcelUnitTest.cpp", "binderBinderUnitTest.cpp"],
     shared_libs: [
         "libbinder",
+        "libcutils",
         "libutils",
     ],
     test_suites: ["general-tests"],