Fix benchmark unit tests.

Add benchmark file dependency in tests instead of using hard-coded
path to bionic-benchmarks.

In addition, add a TEST_MAPPING file so the tests run when benchmark files change.

Test: All unit tests pass.
Test: Ran atest bionic-benchmarks-tests.
Change-Id: I95608f5b5e75d9d74930960a2431c9896b621ce8

benchmarks/Android.bp

@@ -154,7 +154,13 @@ cc_test {
         "libbase",
         "libBionicBenchmarksUtils",
     ],
-    data: ["test_suites/*"],
+    data: [
+        "test_suites/*",
+        "suites/*",
+        ":bionic-benchmarks",
+    ],
+    test_suites: ["device-tests"],
+    require_root: true,
 }
 
 cc_binary {

benchmarks/TEST_MAPPING

@@ -0,0 +1,7 @@
+{
+  "presubmit": [
+    {
+      "name": "bionic-benchmarks-tests"
+    }
+  ]
+}