add the test config lib to a target that is used in platform build

There are tests that uses aconfig flag libs that are not used by actual
platform build. So querying these flags will fail in new storage as they
are not present in storage files. Short term fix is to add them to
platform build depdenency.

Change-Id: I8b485ad65e2fa91258165c3a15c5d509b30d4018
diff --git a/tools/aconfig/aflags/Android.bp b/tools/aconfig/aflags/Android.bp
index 2040cc6..56c4ec0 100644
--- a/tools/aconfig/aflags/Android.bp
+++ b/tools/aconfig/aflags/Android.bp
@@ -20,6 +20,10 @@
         "libnix",
         "libprotobuf",
         "libregex",
+        // TODO: b/371021174 remove this fake dependency once we find a proper strategy to
+        // deal with test aconfig libs are not present in storage because they are never used
+        // by the actual build
+        "libaconfig_test_rust_library",
     ],
 }