Add MetricsProcessor to calculate metrics stats

This CL adds MetricsProcessor class to calculate metrics stats
for both device tests and host tests.

Test: atest MicrodroidBenchmarks
Change-Id: I4f742d6800f14c857a5d0e0718e09870e8ca6547
diff --git a/tests/benchmark/Android.bp b/tests/benchmark/Android.bp
index 0d1cd91..bf78202 100644
--- a/tests/benchmark/Android.bp
+++ b/tests/benchmark/Android.bp
@@ -10,6 +10,7 @@
     srcs: ["src/java/**/*.java"],
     static_libs: [
         "MicrodroidDeviceTestHelper",
+        "MicrodroidTestHelper",
         "androidx.test.runner",
         "androidx.test.ext.junit",
         "com.android.microdroid.testservice-java",