[gn] add missing suppressions for linker warnings on windows

test/cctest/BUILD.gn

 # Copyright 2016 The V8 project authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # The sources are kept automatically in sync with cctest.gyp.
 
 import("../../gni/v8.gni")
 
 gypi_values = exec_script("//build/gypi_to_gn.py",
                           [ rebase_path("cctest.gyp") ],
@@ skipping 142 matching lines @@
     "//build/config/sanitizers:deps",
     "//build/win:default_exe_manifest",
   ]
 
   if (is_component_build) {
     # Same as cctest, we need to depend on the underlying static target.
     deps += [ "../..:v8_maybe_snapshot" ]
   } else {
     deps += [ "../..:v8" ]
   }
+
+  if (is_win) {
+    # Suppress warnings about importing locally defined symbols.
+    if (is_component_build) {
+      ldflags = [
+        "/ignore:4049",
+        "/ignore:4217",
+      ]
+    }
+  }
 }