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.
* Revert "port more ops to JSON (#2809)"
This reverts commit 137f33733d.
* Revert "port ops to JSON: compiler, errors, fetch, files (#2804)"
This reverts commit 79f82cf10e.
* Revert "Port rest of os ops to JSON (#2802)"
This reverts commit 5b2baa5c99.
