Revert "[gn] Consolidate exec_script calls to speed up generation"

runtime/bin/gypi_contents.gni

Index: runtime/bin/gypi_contents.gni
diff --git a/runtime/bin/gypi_contents.gni b/runtime/bin/gypi_contents.gni
deleted file mode 100644
index 34fc2692964e448ee94fd19e726ac869670ce8c9..0000000000000000000000000000000000000000
--- a/runtime/bin/gypi_contents.gni
+++ /dev/null
@@ -1,43 +0,0 @@
-# Copyright (c) 2016, 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.
-
-_gypi_files = [
-  "builtin_sources.gypi",
-  "builtin_impl_sources.gypi",
-  "vmservice/vmservice_sources.gypi",
-  "io_sources.gypi",
-  "io_impl_sources.gypi",
-]
-
-_gypi_contents = exec_script("../../tools/gypi_to_gn.py",
-                             rebase_path(_gypi_files) + [ "--prefix" ],
-                             "scope",
-                             _gypi_files)
-
-resources_sources_gypi = _gypi_contents.vmservice_sources_sources
-
-builtin_sources_gypi = _gypi_contents.builtin_sources_sources
-builtin_impl_sources_gypi = _gypi_contents.builtin_impl_sources_sources
-
-io_sources_gypi = _gypi_contents.io_sources_sources
-io_impl_sources_gypi = _gypi_contents.io_impl_sources_sources
-
-_test_gypi_files = [
-  "../vm/vm_sources.gypi",
-  "builtin_impl_sources.gypi",
-]
-
-_test_only_gypi_contents = exec_script("../../tools/gypi_to_gn.py",
-                                       rebase_path(_test_gypi_files) + [
-                                             "--keep_only=_test.cc",
-                                             "--keep_only=_test.h",
-                                             "--prefix",
-                                           ],
-                                       "scope",
-                                       _test_gypi_files)
-
-# The VM sources are already included in libdart, so we just want to add in
-# the tests here.
-vm_tests_list = _test_only_gypi_contents.vm_sources_sources
-builtin_impl_tests_list = _test_only_gypi_contents.builtin_impl_sources_sources