Fix tests

src/core/lib/gprpp/thd_posix.cc

@@ -108,13 +108,14 @@ class ThreadInternalsPosix
                           }
                           gpr_mu_unlock(&arg.thread->mu_);
 
+                          if (!arg.joinable) {
+                            grpc_core::Delete(arg.thread);
+                          }
+
                           (*arg.body)(arg.arg);
                           if (arg.tracked) {
                             grpc_core::Fork::DecThreadCount();
                           }
-                          if (!arg.joinable) {
-                            grpc_core::Delete(arg.thread);
-                          }
                           return nullptr;
                         },
                         info) == 0);

test/core/client_channel/resolvers/dns_resolver_cooldown_test.cc

@@ -26,6 +26,7 @@
 #include "src/core/lib/gprpp/memory.h"
 #include "src/core/lib/iomgr/combiner.h"
 #include "src/core/lib/iomgr/sockaddr_utils.h"
+#include "src/core/lib/surface/init.h"
 #include "test/core/util/test_config.h"
 
 constexpr int kMinResolutionPeriodMs = 1000;
@@ -279,6 +280,7 @@ int main(int argc, char** argv) {
     GRPC_COMBINER_UNREF(g_combiner, "test");
   }
   grpc_shutdown();
+  grpc_maybe_wait_for_async_shutdown();
   GPR_ASSERT(g_all_callbacks_invoked);
   return 0;
 }