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_hostside/Android.bp b/tests/benchmark_hostside/Android.bp
index 354a260..c5c7571 100644
--- a/tests/benchmark_hostside/Android.bp
+++ b/tests/benchmark_hostside/Android.bp
@@ -12,6 +12,7 @@
     ],
     static_libs: [
         "MicrodroidHostTestHelper",
+        "MicrodroidTestHelper",
     ],
     test_suites: [
         "general-tests",