debuggerd: add pause time benchmark.

Add a benchmark to measure how long we pause a process when dumping.

Bug: http://b/62112103
Test: manually ran it
Change-Id: Iceec2f722915b0ae26144c86dcbeb35793f963da
diff --git a/debuggerd/Android.bp b/debuggerd/Android.bp
index c473e33..7fec47d 100644
--- a/debuggerd/Android.bp
+++ b/debuggerd/Android.bp
@@ -218,6 +218,16 @@
     },
 }
 
+cc_benchmark {
+    name: "debuggerd_benchmark",
+    defaults: ["debuggerd_defaults"],
+    srcs: ["debuggerd_benchmark.cpp"],
+    shared_libs: [
+        "libbase",
+        "libdebuggerd_client",
+    ],
+}
+
 cc_binary {
     name: "crash_dump",
     srcs: [