[devicelab] reland: reduce iterations of startup test, use application binary (#68532)

These devicelab tests are incredibly flaky. Currently they will build & install the same application 15 times. This causes the temp storage to fill up on android, and has a good chance of flaking on iOS due to install issues.

The change from 3 to 15 increased total test time for 2 -> 12 minutes on iOS, or roughly 5 more test equivalents for every single iOS test. Reduce the iteration count back to 5

Uninstall the app after each run so temp storage does not fill up.

dev/devicelab/lib/tasks/perf_tests.dart

@@ -454,24 +454,58 @@ class StartupTest {
 
   Future<TaskResult> run() async {
     return await inDirectory<TaskResult>(testDirectory, () async {
-      final String deviceId = (await devices.workingDevice).deviceId;
-      await flutter('packages', options: <String>['get']);
-
-      const int iterations = 15;
+      final Device device = await devices.workingDevice;
+      const int iterations = 5;
       final List<Map<String, dynamic>> results = <Map<String, dynamic>>[];
-      for (int i = 0; i < iterations; ++i) {
+
+      section('Building application');
+      String applicationBinaryPath;
+      switch (deviceOperatingSystem) {
+        case DeviceOperatingSystem.android:
+          await flutter('build', options: <String>[
+            'apk',
+            '-v',
+            '--profile',
+            '--target-platform=android-arm,android-arm64',
+            '--machine',
+          ]);
+          applicationBinaryPath = '$testDirectory/build/app/outputs/flutter-apk/app-profile.apk';
+          break;
+        case DeviceOperatingSystem.ios:
+          await flutter('build', options: <String>[
+            'ios',
+             '-v',
+            '--profile',
+            '--machine',
+          ]);
+          applicationBinaryPath = _findIosAppInBuildDirectory('$testDirectory/build/ios/iphoneos');
+          break;
+        case DeviceOperatingSystem.fuchsia:
+        case DeviceOperatingSystem.fake:
+          break;
+      }
+
+      for (int i = 0; i < iterations; i += 1) {
         await flutter('run', options: <String>[
           '--no-android-gradle-daemon',
           '--verbose',
           '--profile',
           '--trace-startup',
           '-d',
-          deviceId,
+          device.deviceId,
+          if (applicationBinaryPath != null)
+            '--use-application-binary=$applicationBinaryPath',
         ]);
         final Map<String, dynamic> data = json.decode(
           file('$testDirectory/build/start_up_info.json').readAsStringSync(),
         ) as Map<String, dynamic>;
         results.add(data);
+
+        await flutter('install', options: <String>[
+          '--uninstall-only',
+          '-d',
+          device.deviceId,
+        ]);
       }
 
       final Map<String, dynamic> averageResults = _average(results, iterations);
@@ -1428,3 +1462,12 @@ class _UnzipListEntry {
   final int compressedSize;
   final String path;
 }
+
+String _findIosAppInBuildDirectory(String searchDirectory) {
+  for (final FileSystemEntity entity in Directory(searchDirectory).listSync()) {
+    if (entity.path.endsWith('.app')) {
+      return entity.path;
+    }
+  }
+  return null;
+}