Fix iOS build (#28995)

* Fix iOS compiler

* fix

src/core/lib/gprpp/time.cc

@@ -32,9 +32,9 @@ std::atomic<int64_t> g_process_epoch_seconds;
 std::atomic<gpr_cycle_counter> g_process_epoch_cycles;
 
 GPR_ATTRIBUTE_NOINLINE std::pair<int64_t, gpr_cycle_counter> InitTime() {
-  gpr_cycle_counter cycles_start;
+  gpr_cycle_counter cycles_start = 0;
-  gpr_cycle_counter cycles_end;
+  gpr_cycle_counter cycles_end = 0;
-  int64_t process_epoch_seconds;
+  int64_t process_epoch_seconds = 0;
 
   // Check the current time... if we end up with zero, try again after 100ms.
   // If it doesn't advance after sleeping for 1100ms, crash the process.

test/core/iomgr/ios/CFStreamTests/CFStreamEndpointTests.mm

@@ -127,7 +127,8 @@ static bool compare_slice_buffer_with_buffer(grpc_slice_buffer *slices, const ch
   const grpc_channel_args *args =
       grpc_core::CoreConfiguration::Get().channel_args_preconditioning().PreconditionChannelArgs(
           nullptr);
-  grpc_tcp_client_connect(&done, &ep_, nullptr, args, &resolved_addr, GRPC_MILLIS_INF_FUTURE);
+  grpc_tcp_client_connect(&done, &ep_, nullptr, args, &resolved_addr,
+                          grpc_core::Timestamp::InfFuture());
   grpc_channel_args_destroy(args);
 
   /* await the connection */