chore: add diagnostics to patch call

Author: fuzzybinary

scripts/build_helpers/bin/build_dart.dart

@@ -162,6 +162,8 @@ Future<bool> _patchDartSdk() async {
     logger.i("Patching the Dart SDK to create libdart");
     var result = await Process.run('git', ['apply', '../../dart_sdk.patch'],
         runInShell: true);
+    logger.d("[patch-stdout] ${result.stdout}");
+    logger.d("[patch-stderr] ${result.stderr}");
     logger.d('Patch result is ${result.exitCode}');
     return result.exitCode;
   });