Add build config for grpc++ for Android

* Add shared library libgrpc++_unsecure
* Add host build target protoc-gen-grpc-cpp-plugin and
  protoc-gen-grpc-python-plugin

Test: compile
Change-Id: I5f68da1b1725bfa2f2c412034dfa4d9dc26577c4
diff --git a/TEST_MAPPING b/TEST_MAPPING
new file mode 100644
index 0000000..9b5629f
--- /dev/null
+++ b/TEST_MAPPING
@@ -0,0 +1,8 @@
+{
+  "postsubmit" : [
+    {
+      "name" : "alarm_test",
+      "host" : true
+    }
+  ]
+}