Make LegacyTypeTracker testable

...and add basic trivial tests for it.

Test: this, and ConnectivityServiceTest
Bug: 62650382
Change-Id: Ie7ca938e6f66f1b15feb6ed93afa0aebb20884ae
diff --git a/tests/net/Android.bp b/tests/net/Android.bp
index c8ef82e..3ff862c 100644
--- a/tests/net/Android.bp
+++ b/tests/net/Android.bp
@@ -64,7 +64,7 @@
 android_test {
     name: "FrameworksNetTests",
     defaults: ["FrameworksNetTests-jni-defaults"],
-    srcs: ["java/**/*.java"],
+    srcs: ["java/**/*.java", "java/**/*.kt"],
     platform_apis: true,
     test_suites: ["device-tests"],
     certificate: "platform",