enable lint prefer_equal_for_default_values (#18156)

diff --git a/packages/flutter_tools/lib/src/devfs.dart b/packages/flutter_tools/lib/src/devfs.dart
index eaf1248..846b7de 100644
--- a/packages/flutter_tools/lib/src/devfs.dart
+++ b/packages/flutter_tools/lib/src/devfs.dart
@@ -403,12 +403,12 @@
     String target,
     AssetBundle bundle,
     DateTime firstBuildTime,
-    bool bundleFirstUpload: false,
-    bool bundleDirty: false,
+    bool bundleFirstUpload = false,
+    bool bundleDirty = false,
     Set<String> fileFilter,
     ResidentCompiler generator,
     String dillOutputPath,
-    bool fullRestart: false,
+    bool fullRestart = false,
     String projectRootPath,
   }) async {
     // Mark all entries as possibly deleted.
@@ -575,7 +575,7 @@
   bool _shouldSkip(FileSystemEntity file,
                    String relativePath,
                    Uri directoryUriOnDevice, {
-                   bool ignoreDotFiles: true,
+                   bool ignoreDotFiles = true,
                    }) {
     if (file is Directory) {
       // Skip non-files.
@@ -609,7 +609,7 @@
   Future<bool> _scanFilteredDirectory(Set<String> fileFilter,
                                       Directory directory,
                                       {Uri directoryUriOnDevice,
-                                       bool ignoreDotFiles: true}) async {
+                                       bool ignoreDotFiles = true}) async {
     directoryUriOnDevice =
         _directoryUriOnDevice(directoryUriOnDevice, directory);
     try {
@@ -640,8 +640,8 @@
   /// Scan all files in [directory] that pass various filters (e.g. ignoreDotFiles).
   Future<bool> _scanDirectory(Directory directory,
                               {Uri directoryUriOnDevice,
-                               bool recursive: false,
-                               bool ignoreDotFiles: true,
+                               bool recursive = false,
+                               bool ignoreDotFiles = true,
                                Set<String> fileFilter}) async {
     directoryUriOnDevice = _directoryUriOnDevice(directoryUriOnDevice, directory);
     if ((fileFilter != null) && fileFilter.isNotEmpty) {