Add a test for OptimizingCompileDispatcher::Flush's non-blocking behavior

test/unittests/BUILD.gn

 # Copyright 2016 The V8 project authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("../../gni/v8.gni")
 
 v8_executable("unittests") {
   testonly = true
 
   sources = [
@@ skipping 15 matching lines @@
     "base/platform/time-unittest.cc",
     "base/sys-info-unittest.cc",
     "base/utils/random-number-generator-unittest.cc",
     "cancelable-tasks-unittest.cc",
     "char-predicates-unittest.cc",
     "compiler-dispatcher/compiler-dispatcher-helper.cc",
     "compiler-dispatcher/compiler-dispatcher-helper.h",
     "compiler-dispatcher/compiler-dispatcher-job-unittest.cc",
     "compiler-dispatcher/compiler-dispatcher-tracer-unittest.cc",
     "compiler-dispatcher/compiler-dispatcher-unittest.cc",
+    "compiler-dispatcher/optimizing-compile-dispatcher-unittest.cc",
     "compiler/branch-elimination-unittest.cc",
     "compiler/bytecode-analysis-unittest.cc",
     "compiler/checkpoint-elimination-unittest.cc",
     "compiler/common-operator-reducer-unittest.cc",
     "compiler/common-operator-unittest.cc",
     "compiler/compiler-test-utils.h",
     "compiler/control-equivalence-unittest.cc",
     "compiler/control-flow-optimizer-unittest.cc",
     "compiler/dead-code-elimination-unittest.cc",
     "compiler/diamond-unittest.cc",
@@ skipping 140 matching lines @@
     deps += [ "//third_party/icu" ]
   }
 
   if (is_win) {
     # This warning is benignly triggered by the U16 and U32 macros in
     # bytecode-utils.h.
     # C4309: 'static_cast': truncation of constant value
     cflags = [ "/wd4309" ]
   }
 }