Preload: Add a simple test for the state of classes

Use app_process and reflection to find the class state.

This is expected to break when internals change, so include a test
for expectations.

Bug: 130206915
Test: atest PreloadCheck
Change-Id: I7ecdb88a19efcfcfa1c7aa5c7e67d1990306166e
diff --git a/tools/preload-check/Android.bp b/tools/preload-check/Android.bp
new file mode 100644
index 0000000..c84567b
--- /dev/null
+++ b/tools/preload-check/Android.bp
@@ -0,0 +1,21 @@
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+java_test_host {
+    name: "PreloadCheck",
+    srcs: ["src/**/*.java"],
+    libs: ["tradefed"],
+    test_suites: ["general-tests"],
+    required: ["preload-check-device"],
+}