Remove a bunch of stale entries from our BUILD.gn files.

tools/gn/secondary/third_party/WebKit/Source/wtf/BUILD.gn

 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 config("wtf-config") {
   include_dirs = [ ".." ]
   if (is_win) {
     include_dirs += [ "os-win32" ]
     defines = [
       "__STD_C",
@@ skipping 314 matching lines @@
   sources = [
     "CheckedArithmeticTest.cpp",
     "FunctionalTest.cpp",
     "HashMapTest.cpp",
     "HashSetTest.cpp",
     "ListHashSetTest.cpp",
     "MathExtrasTest.cpp",
     "PartitionAllocTest.cpp",
     "SHA1Test.cpp",
     "SaturatedArithmeticTest.cpp",
-    "SpinLockTest.cpp",
     "StringExtrasTest.cpp",
     "StringHasherTest.cpp",
     "TemporaryChangeTest.cpp",
     "VectorTest.cpp",
     "testing/WTFTestHelpers.h",
     "text/CStringTest.cpp",
     "text/StringBuilderTest.cpp",
     "text/StringImplTest.cpp",
     "text/StringOperatorsTest.cpp",
     "text/WTFStringTest.cpp",
@@ skipping 11 matching lines @@
   #  # Disable c4267 warnings until we fix size_t to int truncations.
 # 'msvs_disabled_warnings': [4127, 4355, 4510, 4512, 4610, 4706, 4068, 4267],
 
 #  if (is_linux && use_tcmalloc) {
 #     deps += [
 #      "//base:base",
 #      "//base/allocator:allocator",
 #    ],
 #  }
 }