Fix --preview-dart2 option handling for ios profile/release. (#13285)

* Fix --preview-dart2 option handling for ios profile/release.

* Remove unused parameter

packages/flutter_tools/lib/src/commands/build_ios.dart

@@ -73,7 +73,6 @@ class BuildIOSCommand extends BuildSubCommand {
       target: targetFile,
       buildForDevice: !forSimulator,
       codesign: shouldCodesign,
-      previewDart2 : argResults['preview-dart-2'],
     );
 
     if (!result.success) {

packages/flutter_tools/lib/src/fuchsia/fuchsia_device.dart

@@ -65,7 +65,6 @@ class FuchsiaDevice extends Device {
     DebuggingOptions debuggingOptions,
     Map<String, dynamic> platformArgs,
     bool prebuiltApplication: false,
-    bool previewDart2: false,
     bool applicationNeedsRebuild: false,
     bool usesTerminalUi: false,
     bool ipv6: false,

packages/flutter_tools/lib/src/ios/devices.dart

@@ -154,7 +154,6 @@ class IOSDevice extends Device {
     DebuggingOptions debuggingOptions,
     Map<String, dynamic> platformArgs,
     bool prebuiltApplication: false,
-    bool previewDart2: false,
     bool applicationNeedsRebuild: false,
     bool usesTerminalUi: true,
     bool ipv6: false,

packages/flutter_tools/lib/src/ios/mac.dart

@@ -205,7 +205,6 @@ Future<XcodeBuildResult> buildXcodeProject({
   bool buildForDevice,
   bool codesign: true,
   bool usesTerminalUi: true,
-  bool previewDart2: false,
 }) async {
   if (!_checkXcodeVersion())
     return new XcodeBuildResult(success: false);
@@ -266,7 +265,7 @@ Future<XcodeBuildResult> buildXcodeProject({
     buildInfo: buildInfo,
     target: target,
     hasPlugins: hasFlutterPlugins,
-    previewDart2: previewDart2,
+    previewDart2: buildInfo.previewDart2,
   );
 
   final List<String> commands = <String>[

packages/flutter_tools/lib/src/ios/simulators.dart

@@ -297,7 +297,6 @@ class IOSSimulator extends Device {
     String route,
     DebuggingOptions debuggingOptions,
     Map<String, dynamic> platformArgs,
-    bool previewDart2: false,
     bool prebuiltApplication: false,
     bool applicationNeedsRebuild: false,
     bool usesTerminalUi: true,