Add icu libraries to unittests dependencies

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 152 matching lines @@
   deps = [
     "../..:v8",
     "../..:v8_libbase",
     "../..:v8_libplatform",
     "//build/config/sanitizers:deps",
     "//build/win:default_exe_manifest",
     "//testing/gmock",
     "//testing/gtest",
   ]
 
+  if (v8_enable_i18n_support) {
+    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" ]
   }
 }