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, 5 insertions, 5 deletions

diff --git a/js/body.ts b/js/body.ts
index b1f1af8a5..6567b1934 100644
--- a/js/body.ts
+++ b/js/body.ts
@@ -1,8 +1,8 @@
-import * as formData from "./form_data";
-import * as blob from "./blob";
-import * as encoding from "./text_encoding";
-import * as headers from "./headers";
-import * as domTypes from "./dom_types";
+import * as formData from "./form_data.ts";
+import * as blob from "./blob.ts";
+import * as encoding from "./text_encoding.ts";
+import * as headers from "./headers.ts";
+import * as domTypes from "./dom_types.ts";
 
 const { Headers } = headers;