Refactor snapshot build (#2825)

Instead of using core/snapshot_creator.rs, instead two crates are
introduced which allow building the snapshot during build.rs.

Rollup is removed and replaced with our own bundler. This removes
the Node build dependency. Modules in //js now use Deno-style imports
with file extensions, rather than Node style extensionless imports.

This improves incremental build time when changes are made to //js files
by about 40 seconds.

1 files changed, 3 insertions, 3 deletions

diff --git a/js/request.ts b/js/request.ts
index 5ed1e9d63..f7a3cdfc1 100644
--- a/js/request.ts
+++ b/js/request.ts
@@ -1,7 +1,7 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
-import * as headers from "./headers";
-import * as body from "./body";
-import * as domTypes from "./dom_types";
+import * as headers from "./headers.ts";
+import * as body from "./body.ts";
+import * as domTypes from "./dom_types.ts";
 
 const { Headers } = headers;