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

runtime/vm/gypi_contents.gni

Index: runtime/vm/gypi_contents.gni
diff --git a/runtime/vm/gypi_contents.gni b/runtime/vm/gypi_contents.gni
deleted file mode 100644
index ac013cb96e3daf9cbec3dc63fd4d1f516ed199a4..0000000000000000000000000000000000000000
--- a/runtime/vm/gypi_contents.gni
+++ /dev/null
@@ -1,54 +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.
-
-_core_library_names = [
-  "async",
-  "core",
-  "collection",
-  "convert",
-  "developer",
-  "internal",
-  "isolate",
-  "math",
-  "mirrors",
-  "profiler",
-  "typed_data",
-  "vmservice",
-]
-
-_core_library_gypis = [
-  "../platform/platform_headers.gypi",
-  "../platform/platform_sources.gypi",
-  "../vm/vm_sources.gypi",
-  "../lib/async_sources.gypi",
-  "../lib/core_sources.gypi",
-  "../lib/collection_sources.gypi",
-  "../lib/convert_sources.gypi",
-  "../lib/developer_sources.gypi",
-  "../lib/internal_sources.gypi",
-  "../lib/isolate_sources.gypi",
-  "../lib/math_sources.gypi",
-  "../lib/mirrors_sources.gypi",
-  "../lib/typed_data_sources.gypi",
-  "../lib/vmservice_sources.gypi",
-  "../../sdk/lib/async/async_sources.gypi",
-  "../../sdk/lib/collection/collection_sources.gypi",
-  "../../sdk/lib/convert/convert_sources.gypi",
-  "../../sdk/lib/core/core_sources.gypi",
-  "../../sdk/lib/developer/developer_sources.gypi",
-  "../../sdk/lib/internal/internal_sources.gypi",
-  "../../sdk/lib/isolate/isolate_sources.gypi",
-  "../../sdk/lib/math/math_sources.gypi",
-  "../../sdk/lib/mirrors/mirrors_sources.gypi",
-  "../../sdk/lib/profiler/profiler_sources.gypi",
-  "../../sdk/lib/vmservice/vmservice_sources.gypi",
-  "../bin/io_sources.gypi",
-]
-
-processed_gypis = exec_script("../../tools/process_gypis.py",
-                              _core_library_names,
-                              "scope",
-                              _core_library_gypis)
-
-