Update bootstat_test to really work host-side

bootstat_test is marked host_supported:true but use
a AndroidTest.xml config that can only work for device.

Deleting the explict config to rely on the auto-gen ones.
Adding unit_tests:true to run in presubmit

Test: presubmit, atest bootstat_tests --host
Bug: 179092189
Change-Id: Ib6694f760d9ef5f867cd1982f7e1fe65ce9dd62d

bootstat/Android.bp

@@ -93,4 +93,7 @@ cc_test {
         "boot_event_record_store_test.cpp",
         "testrunner.cpp",
     ],
+    test_options: {
+        unit_test: true,
+    },
 }

bootstat/AndroidTest.xml

@@ -1,26 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!-- Copyright (C) 2017 The Android Open Source Project
-
-     Licensed under the Apache License, Version 2.0 (the "License");
-     you may not use this file except in compliance with the License.
-     You may obtain a copy of the License at
-
-          http://www.apache.org/licenses/LICENSE-2.0
-
-     Unless required by applicable law or agreed to in writing, software
-     distributed under the License is distributed on an "AS IS" BASIS,
-     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-     See the License for the specific language governing permissions and
-     limitations under the License.
--->
-<configuration description="Config for bootstat_tests">
-    <target_preparer class="com.android.tradefed.targetprep.PushFilePreparer">
-        <option name="cleanup" value="true" />
-        <option name="push" value="bootstat_tests->/data/local/tmp/bootstat_tests" />
-    </target_preparer>
-    <option name="test-suite-tag" value="apct" />
-    <test class="com.android.tradefed.testtype.GTest" >
-        <option name="native-test-device-path" value="/data/local/tmp" />
-        <option name="module-name" value="bootstat_tests" />
-    </test>
-</configuration>