Plugins loaded by the `@kbn/interpreter` can sometimes setup global values while loading, like the regeneratorRuntime for instance, but the current plugin loading code is deleting every global that was added during plugin load. This changes the logic to only cleanup the `canvas` global after loading the canvas plugins.
resolves https://github.com/elastic/kibana/issues/27162
* [@kbn/interpreter] improve build/packaging (#26096)
Summary of changes:
- move all build artifacts under `target` directory
- run babel and webpack in parallel
- support optional watch and sourcemaps in build
- expose /common /public /plugin /server sub-exports as index.js
- avoid importing deeply from `@kbn/interpreter`
- move a couple missed dependencies from x-pack to kibana
- remove custom babel-register implementation
* fix bad conflict resolution
