Prohibit accidental renames of product config json fields

Can be caused by `json:"omitempty"` instead of `json:",omitempty"`

Bug: 69076024
Test: m -j # which runs unit tests
Change-Id: I92e3193d00a740c72d36a56748e0b0a8ad1d772e
diff --git a/Android.bp b/Android.bp
index b57b0cc..e89f908 100644
--- a/Android.bp
+++ b/Android.bp
@@ -64,6 +64,7 @@
         "android/env.go",
     ],
     testSrcs: [
+        "android/config_test.go",
         "android/expand_test.go",
         "android/paths_test.go",
         "android/prebuilt_test.go",