Ensure precache --web works on dev branch (#42289)

diff --git a/packages/flutter_tools/test/general.shard/cache_test.dart b/packages/flutter_tools/test/general.shard/cache_test.dart
index cc6bb62..a6a20a2 100644
--- a/packages/flutter_tools/test/general.shard/cache_test.dart
+++ b/packages/flutter_tools/test/general.shard/cache_test.dart
@@ -209,7 +209,7 @@
   });
 
   test('Unstable artifacts', () {
-    expect(DevelopmentArtifact.web.unstable, true);
+    expect(DevelopmentArtifact.web.unstable, false);
     expect(DevelopmentArtifact.linux.unstable, true);
     expect(DevelopmentArtifact.macOS.unstable, true);
     expect(DevelopmentArtifact.windows.unstable, true);