Remove Chrome OS-related GN build configuration

build/sanitizers/BUILD.gn

 # Copyright (c) 2015 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.
 
-if (is_linux && !is_chromeos) {
+if (is_linux) {
   # TODO(GYP): Figure out which of these work and are needed on other platforms.
   copy("copy_llvm_symbolizer") {
     sources = [
       "//third_party/llvm-build/Release+Asserts/bin/llvm-symbolizer",
     ]
     outputs = [
       "$root_out_dir/llvm-symbolizer",
     ]
   }
 }