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/config/TEST_MAPPING b/config/TEST_MAPPING
new file mode 100644
index 0000000..d09805e
--- /dev/null
+++ b/config/TEST_MAPPING
@@ -0,0 +1,7 @@
+{
+  "presubmit": [
+    {
+      "name": "PreloadCheck"
+    }
+  ]
+}