Use TestDiscardableMemoryAllocator in filter_fuzz_stub.

skia/BUILD.gn

 # Copyright (c) 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.
 
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//testing/test.gni")
 if (current_cpu == "arm") {
   import("//build/config/arm.gni")
 }
@@ skipping 647 matching lines @@
       "ext/image_operations_bench.cc",
     ]
 
     deps = [
       ":skia",
       "//base",
     ]
   }
 
   executable("filter_fuzz_stub") {
+    testonly = true
     sources = [
       "tools/filter_fuzz_stub/filter_fuzz_stub.cc",
     ]
 
     deps = [
       ":skia",
       "//base",
+      "//base/test:test_support",
     ]
   }
 }