Add tests for afdo.go

Bug: 79161490
Test: presubmit
Change-Id: I686b5226aad5011ab30a0a105f8c7866cd610502
diff --git a/cc/Android.bp b/cc/Android.bp
index cf45630..9103a48 100644
--- a/cc/Android.bp
+++ b/cc/Android.bp
@@ -88,6 +88,7 @@
         "stub_library.go",
     ],
     testSrcs: [
+        "afdo_test.go",
         "cc_test.go",
         "compiler_test.go",
         "gen_test.go",