Move sanitizer and symbol flags out of BUILDCONFIG

third_party/brotli/BUILD.gn

 # Copyright 2014 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("brotli_warnings") {
   if (is_clang) {
     # IncrementalCopyFastPath in decode.c can be unused.
     # (The file looks very different upstream, this is probably no longer
     # needed after rolling brotli the next time.)
     cflags = [ "-Wno-unused-function" ]
@@ skipping 23 matching lines @@
 
   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [
     "//build/config/compiler:no_chromium_code",
 
     # Must be after no_chromium_code for warning flags to be ordered correctly.
     ":brotli_warnings",
   ]
 
   # Since we are never debug brotli, freeze the optimizations to -O2.
-  if (is_debug) {
-    configs -= [ "//build/config/compiler:no_optimize" ]
-  } else {
-    configs -= [ "//build/config/compiler:optimize" ]
-  }
+  configs -= [ "//build/config/compiler:default_optimization" ]
   configs += [ "//build/config/compiler:optimize_max" ]
 
   include_dirs = [ "dec" ]
 }