Add support for ignoring the svn revision when getting the version, use this for gn build

runtime/BUILD.gn

 # Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 config("dart_config") {
   defines = []
   if (is_debug) {
     defines += ["DEBUG"]
   } else {
     defines += ["NDEBUG"]
@@ skipping 58 matching lines @@
     "vm/version_in.cc",
   ]
   output = "$target_gen_dir/version.cc"
   outputs = [ output, ]
 
   script = "../tools/make_version.py"
   args = [
     "--quiet",
     "--output", rebase_path(output, root_build_dir),
     "--input", rebase_path("vm/version_in.cc", root_build_dir),
+    "--ignore_svn_revision",
   ]
 }
 
 
 executable("libdart_dependency_helper") {
   deps = [
     "vm:libdart_lib_withcore",
     "vm:libdart_lib",
     "vm:libdart_vm",
     "vm:libdart_platform",
     "third_party/jscre:libjscre",
     "third_party/double-conversion/src:libdouble_conversion",
   ]
   sources = [
     "vm/libdart_dependency_helper.cc",
   ]
 }