prefer_const_declarations on local variables (#14358)

packages/flutter_tools/test/ios/mac_test.dart

diff --git a/packages/flutter_tools/test/ios/mac_test.dart b/packages/flutter_tools/test/ios/mac_test.dart
index 3bdd6e2..7b59f5e 100644
--- a/packages/flutter_tools/test/ios/mac_test.dart
+++ b/packages/flutter_tools/test/ios/mac_test.dart
@@ -113,7 +113,7 @@
     });
 
     testUsingContext('xcodeSelectPath returns path when xcode-select is installed', () {
-      final String xcodePath = '/Applications/Xcode8.0.app/Contents/Developer';
+      const String xcodePath = '/Applications/Xcode8.0.app/Contents/Developer';
       when(mockProcessManager.runSync(<String>['/usr/bin/xcode-select', '--print-path']))
           .thenReturn(new ProcessResult(1, 0, xcodePath, ''));
       expect(xcode.xcodeSelectPath, xcodePath);

packages/flutter_tools/test/ios/xcodeproj_test.dart

diff --git a/packages/flutter_tools/test/ios/xcodeproj_test.dart b/packages/flutter_tools/test/ios/xcodeproj_test.dart
index a8eeb7f..75cec8a 100644
--- a/packages/flutter_tools/test/ios/xcodeproj_test.dart
+++ b/packages/flutter_tools/test/ios/xcodeproj_test.dart
@@ -6,7 +6,7 @@
 void main() {
   group('Xcode project properties', () {
     test('properties from default project can be parsed', () {
-      final String output = '''
+      const String output = '''
 Information about project "Runner":
     Targets:
         Runner
@@ -27,7 +27,7 @@
       expect(info.buildConfigurations, <String>['Debug', 'Release']);
     });
     test('properties from project with custom schemes can be parsed', () {
-      final String output = '''
+      const String output = '''
 Information about project "Runner":
     Targets:
         Runner