Prune at_auth_unlock_unittest out of general-tests.

These tests define test_suite as 'general-tests' only but not used in
Test Mapping Suite. Hence, we plan to prune them to reduce size/build
time of They are listed as below:
 - at_auth_unlock_unittest

Bug: 139893779

Test: m general-tests
Change-Id: Idfed3878a71148f6ae79c084f7d7727fe21c5f82
diff --git a/test/Android.bp b/test/Android.bp
index e3c2f31..057cd1e 100644
--- a/test/Android.bp
+++ b/test/Android.bp
@@ -39,5 +39,4 @@
     test_config: "at_auth_unlock_unittest.xml",
-    test_suites: ["general-tests"],