Remove ASSERT which was reported as a race by ThreadSanitizer

runtime/bin/process_macos.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_MACOS)
 
 #include "bin/process.h"
 
 #include <errno.h>  // NOLINT
@@ skipping 133 matching lines @@
     // Mark write end non-blocking.
     FDUtils::SetNonBlocking(sig_chld_fds_[1]);
 
     // Thread started and the ExitCodeHandler is initialized.
     initialized_ = true;
     return true;
   }
 
   // Get the write end of the pipe.
   static int WakeUpFd() {
-    ASSERT(initialized_);
     return sig_chld_fds_[1];
   }
 
   static void TerminateExitCodeThread() {
     MutexLocker locker(mutex_);
     if (!initialized_) {
       return;
     }
 
     uint8_t data = kThreadTerminateByte;
@@ skipping 536 matching lines @@
 
 
 intptr_t Process::CurrentProcessId() {
   return static_cast<intptr_t>(getpid());
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_MACOS)