Fix benchmark regression from #83427 (#83437)

packages/flutter_tools/lib/src/run_hot.dart

@@ -1241,9 +1241,11 @@ class ProjectFileInvalidator {
       final List<Future<void>> waitList = <Future<void>>[];
       for (final Uri uri in urisToScan) {
         waitList.add(pool.withResource<void>(
-          () => _fileSystem
+          // Calling fs.stat() is more performant than fs.file().stat(), but
-            .file(uri)
+          // uri.toFilePath() does not work with MultiRootFileSystem.
-            .stat()
+          () => (uri.hasScheme && uri.scheme != 'file'
+            ? _fileSystem.file(uri).stat()
+            :  _fileSystem.stat(uri.toFilePath(windows: _platform.isWindows)))
             .then((FileStat stat) {
               final DateTime updatedAt = stat.modified;
               if (updatedAt != null && updatedAt.isAfter(lastCompiled)) {
@@ -1255,7 +1257,11 @@ class ProjectFileInvalidator {
       await Future.wait<void>(waitList);
     } else {
       for (final Uri uri in urisToScan) {
-        final DateTime updatedAt = _fileSystem.file(uri).statSync().modified;
+        // Calling fs.statSync() is more performant than fs.file().statSync(), but
+        // uri.toFilePath() does not work with MultiRootFileSystem.
+        final DateTime updatedAt = uri.hasScheme && uri.scheme != 'file'
+          ? _fileSystem.file(uri).statSync().modified
+          : _fileSystem.statSync(uri.toFilePath(windows: _platform.isWindows)).modified;
         if (updatedAt != null && updatedAt.isAfter(lastCompiled)) {
           invalidatedFiles.add(uri);
         }

packages/flutter_tools/test/general.shard/project_file_invalidator_test.dart

@@ -7,6 +7,7 @@
 import 'package:file/memory.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/logger.dart';
+import 'package:flutter_tools/src/base/multi_root_file_system.dart';
 import 'package:flutter_tools/src/base/platform.dart';
 import 'package:flutter_tools/src/convert.dart';
 import 'package:flutter_tools/src/run_hot.dart';
@@ -164,5 +165,36 @@ void main() {
       expect(nextInvalidationResult.packageConfig,
         isNot(invalidationResult.packageConfig));
     });
+
+    testWithoutContext('Works with MultiRootFileSystem uris, asyncScanning: $asyncScanning', () async {
+      final FileSystem fileSystem = MemoryFileSystem.test();
+      final FileSystem multiRootFileSystem = MultiRootFileSystem(
+        delegate: fileSystem,
+        scheme: 'scheme',
+        roots: <String>[
+          '/root',
+        ],
+      );
+      final ProjectFileInvalidator projectFileInvalidator = ProjectFileInvalidator(
+        fileSystem: multiRootFileSystem,
+        platform: FakePlatform(),
+        logger: BufferLogger.test(),
+      );
+
+      expect(
+        (await projectFileInvalidator.findInvalidated(
+          lastCompiled: inFuture,
+          urisToMonitor: <Uri>[
+            Uri.parse('file1'),
+            Uri.parse('file:///file2'),
+            Uri.parse('scheme:///file3'),
+          ],
+          packagesPath: '.packages',
+          asyncScanning: asyncScanning,
+          packageConfig: PackageConfig.empty,
+        )).uris,
+        isEmpty,
+      );
+    });
   }
 }