[gn] Fix valgrind config

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.
 
 import("//build/config/android/config.gni")
 import("//build/config/arm.gni")
 import("//build/config/dcheck_always_on.gni")
 import("//build/config/mips.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 
@@ skipping 26 matching lines @@
   # Sets -dENABLE_HANDLE_ZAPPING.
   v8_enable_handle_zapping = true
 
   # Enable ECMAScript Internationalization API. Enabling this feature will
   # add a dependency on the ICU library.
   v8_enable_i18n_support = true
 
   # Enable slow dchecks.
   v8_enable_slow_dchecks = false
 
+  # Indicate if valgrind was fetched as a custom deps to make it available on
+  # swarming.
+  v8_has_valgrind = false
+
   # Interpreted regexp engine exists as platform-independent alternative
   # based where the regular expression is compiled to a bytecode.
   v8_interpreted_regexp = false
 
   # Sets -dOBJECT_PRINT.
   v8_object_print = false
 
   # With post mortem support enabled, metadata is embedded into libv8 that
   # describes various parameters of the VM for use by debuggers. See
   # tools/gen-postmortem-metadata.py for details.
@@ skipping 2290 matching lines @@
 
   deps = [
     ":fuzzer_support",
   ]
 
   configs = [ ":internal_config" ]
 }
 
 v8_fuzzer("wasm_asmjs_fuzzer") {
 }