Set the LANG when invoking cocoapods (#45710)

diff --git a/packages/flutter_tools/lib/src/macos/cocoapods.dart b/packages/flutter_tools/lib/src/macos/cocoapods.dart
index 3bfd940..8fb1dd6 100644
--- a/packages/flutter_tools/lib/src/macos/cocoapods.dart
+++ b/packages/flutter_tools/lib/src/macos/cocoapods.dart
@@ -77,7 +77,12 @@
       processUtils.exitsHappy(<String>['which', 'pod']);
 
   Future<String> get cocoaPodsVersionText {
-    _versionText ??= processUtils.run(<String>['pod', '--version']).then<String>((RunResult result) {
+    _versionText ??= processUtils.run(
+      <String>['pod', '--version'],
+      environment: <String, String>{
+        'LANG': 'en_US.UTF-8',
+      },
+    ).then<String>((RunResult result) {
       return result.exitCode == 0 ? result.stdout.trim() : null;
     }, onError: (dynamic _) => null);
     return _versionText;
@@ -305,6 +310,7 @@
         // See https://github.com/flutter/flutter/issues/10873.
         // CocoaPods analytics adds a lot of latency.
         'COCOAPODS_DISABLE_STATS': 'true',
+        'LANG': 'en_US.UTF-8',
       },
     );
     status.stop();
diff --git a/packages/flutter_tools/test/general.shard/macos/cocoapods_test.dart b/packages/flutter_tools/test/general.shard/macos/cocoapods_test.dart
index 44ee1b5..19ae134 100644
--- a/packages/flutter_tools/test/general.shard/macos/cocoapods_test.dart
+++ b/packages/flutter_tools/test/general.shard/macos/cocoapods_test.dart
@@ -80,12 +80,12 @@
     when(mockProcessManager.run(
       <String>['pod', 'install', '--verbose'],
       workingDirectory: 'project/ios',
-      environment: <String, String>{'FLUTTER_FRAMEWORK_DIR': 'engine/path', 'COCOAPODS_DISABLE_STATS': 'true'},
+      environment: <String, String>{'FLUTTER_FRAMEWORK_DIR': 'engine/path', 'COCOAPODS_DISABLE_STATS': 'true', 'LANG': 'en_US.UTF-8'},
     )).thenAnswer((_) async => exitsHappy());
     when(mockProcessManager.run(
       <String>['pod', 'install', '--verbose'],
       workingDirectory: 'project/macos',
-      environment: <String, String>{'FLUTTER_FRAMEWORK_DIR': 'engine/path', 'COCOAPODS_DISABLE_STATS': 'true'},
+      environment: <String, String>{'FLUTTER_FRAMEWORK_DIR': 'engine/path', 'COCOAPODS_DISABLE_STATS': 'true', 'LANG': 'en_US.UTF-8'},
     )).thenAnswer((_) async => exitsHappy());
   });
 
@@ -368,6 +368,7 @@
         environment: <String, String>{
           'FLUTTER_FRAMEWORK_DIR': 'engine/path',
           'COCOAPODS_DISABLE_STATS': 'true',
+          'LANG': 'en_US.UTF-8',
         },
       )).thenAnswer((_) async => exitsWithError(
         '''
@@ -420,7 +421,7 @@
       verify(mockProcessManager.run(
         <String>['pod', 'install', '--verbose'],
         workingDirectory: 'project/ios',
-        environment: <String, String>{'FLUTTER_FRAMEWORK_DIR': 'engine/path', 'COCOAPODS_DISABLE_STATS': 'true'},
+        environment: <String, String>{'FLUTTER_FRAMEWORK_DIR': 'engine/path', 'COCOAPODS_DISABLE_STATS': 'true', 'LANG': 'en_US.UTF-8'},
       ));
     }, overrides: <Type, Generator>{
       FileSystem: () => fs,
@@ -447,6 +448,7 @@
         environment: <String, String>{
           'FLUTTER_FRAMEWORK_DIR': 'engine/path',
           'COCOAPODS_DISABLE_STATS': 'true',
+          'LANG': 'en_US.UTF-8',
         },
       ));
     }, overrides: <Type, Generator>{
@@ -477,6 +479,7 @@
         environment: <String, String>{
           'FLUTTER_FRAMEWORK_DIR': 'engine/path',
           'COCOAPODS_DISABLE_STATS': 'true',
+          'LANG': 'en_US.UTF-8',
         },
       ));
     }, overrides: <Type, Generator>{
@@ -507,6 +510,7 @@
         environment: <String, String>{
           'FLUTTER_FRAMEWORK_DIR': 'engine/path',
           'COCOAPODS_DISABLE_STATS': 'true',
+          'LANG': 'en_US.UTF-8',
         },
       ));
     }, overrides: <Type, Generator>{
@@ -539,6 +543,7 @@
         environment: <String, String>{
           'FLUTTER_FRAMEWORK_DIR': 'engine/path',
           'COCOAPODS_DISABLE_STATS': 'true',
+          'LANG': 'en_US.UTF-8',
         },
       ));
     }, overrides: <Type, Generator>{
@@ -591,6 +596,7 @@
         environment: <String, String>{
           'FLUTTER_FRAMEWORK_DIR': 'engine/path',
           'COCOAPODS_DISABLE_STATS': 'true',
+          'LANG': 'en_US.UTF-8',
         },
       )).thenAnswer(
         (_) async => exitsWithError()
@@ -621,6 +627,7 @@
         'FLUTTER_FRAMEWORK_DIR': 'engine/path',
         'COCOAPODS_DISABLE_STATS': 'true',
         'CP_REPOS_DIR': cocoapodsRepoDir,
+        'LANG': 'en_US.UTF8',
       };
     });
 
@@ -629,7 +636,6 @@
       fs.file(fs.path.join('project', 'ios', 'Podfile'))
         ..createSync()
         ..writeAsStringSync('Existing Podfile');
-
       when(mockProcessManager.run(
         <String>['pod', 'install', '--verbose'],
         workingDirectory: 'project/ios',