[experiments] retry work_serializer_dispatch with posix (#37839)

All known flakes/bugs have been fixed.

<!--

If you know who should review your pull request, please assign it to that
person, otherwise the pull request would get assigned randomly.

If your pull request is for a specific language, please add the appropriate
lang label.

-->

Closes #37839

COPYBARA_INTEGRATE_REVIEW=https://github.com/grpc/grpc/pull/37839 from yousukseung:work_serializer_dispatch a82a068ebf
PiperOrigin-RevId: 681609545

bazel/experiments.bzl

@@ -138,10 +138,6 @@ EXPERIMENTS = {
             "core_end2end_test": [
                 "event_engine_client",
                 "local_connector_secure",
-                "work_serializer_dispatch",
-            ],
-            "cpp_end2end_test": [
-                "work_serializer_dispatch",
             ],
             "endpoint_test": [
                 "tcp_frame_size_tuning",
@@ -155,16 +151,10 @@ EXPERIMENTS = {
                 "tcp_frame_size_tuning",
                 "tcp_rcv_lowat",
             ],
-            "lb_unit_test": [
-                "work_serializer_dispatch",
-            ],
             "resource_quota_test": [
                 "free_large_allocator",
                 "unconstrained_max_quota_buffer_size",
             ],
-            "xds_end2end_test": [
-                "work_serializer_dispatch",
-            ],
         },
         "on": {
             "cancel_ares_query_test": [
@@ -172,6 +162,10 @@ EXPERIMENTS = {
             ],
             "core_end2end_test": [
                 "event_engine_listener",
+                "work_serializer_dispatch",
+            ],
+            "cpp_end2end_test": [
+                "work_serializer_dispatch",
             ],
             "cpp_lb_end2end_test": [
                 "pick_first_new",
@@ -181,12 +175,14 @@ EXPERIMENTS = {
             ],
             "lb_unit_test": [
                 "pick_first_new",
+                "work_serializer_dispatch",
             ],
             "resolver_component_tests_runner_invoker": [
                 "event_engine_dns",
             ],
             "xds_end2end_test": [
                 "pick_first_new",
+                "work_serializer_dispatch",
             ],
         },
     },

src/core/lib/experiments/experiments.cc

@@ -462,7 +462,7 @@ const ExperimentMetadata g_experiment_metadata[] = {
      additional_constraints_work_serializer_clears_time_cache, nullptr, 0, true,
      true},
     {"work_serializer_dispatch", description_work_serializer_dispatch,
-     additional_constraints_work_serializer_dispatch, nullptr, 0, false, true},
+     additional_constraints_work_serializer_dispatch, nullptr, 0, true, true},
 };
 
 }  // namespace grpc_core

src/core/lib/experiments/experiments.h

@@ -155,7 +155,8 @@ inline bool IsTraceRecordCallopsEnabled() { return true; }
 inline bool IsUnconstrainedMaxQuotaBufferSizeEnabled() { return false; }
 #define GRPC_EXPERIMENT_IS_INCLUDED_WORK_SERIALIZER_CLEARS_TIME_CACHE
 inline bool IsWorkSerializerClearsTimeCacheEnabled() { return true; }
-inline bool IsWorkSerializerDispatchEnabled() { return false; }
+#define GRPC_EXPERIMENT_IS_INCLUDED_WORK_SERIALIZER_DISPATCH
+inline bool IsWorkSerializerDispatchEnabled() { return true; }
 #endif
 
 #else

src/core/lib/experiments/rollouts.yaml

@@ -112,6 +112,6 @@
   default:
     # TODO(ysseung): Not fully tested.
     ios: broken
-    posix: false
+    posix: true
     # TODO(ysseung): Test flakes not fully resolved.
     windows: broken