Really disable shuffling for gen_defaults tests (#142721)

https://github.com/flutter/flutter/issues/142716

dev/tools/gen_defaults/dart_test.yaml

diff --git a/dev/tools/gen_defaults/dart_test.yaml b/dev/tools/gen_defaults/dart_test.yaml
new file mode 100644
index 0000000..fb3b8a2
--- /dev/null
+++ b/dev/tools/gen_defaults/dart_test.yaml
@@ -0,0 +1,5 @@
+tags:
+  # This tag tells the test framework to not shuffle the test order according to
+  # the --test-randomize-ordering-seed for the suites that have this tag.
+  no-shuffle:
+    allow_test_randomization: false