Ref #3712. This change allowed the deno_typescript crate to reference
cli/js/lib.deno_runtime.d.ts which breaks "cargo package". We intend to
reintroduce a revised version of this patch later once "cargo
package" is working and tested.
This reverts commit 737ab94ea1.
* refactored RecursiveLoad - it was renamed to RecursiveModuleLoad, it does not take ownership of isolate anymore - a struct implementing Stream that yields SourceCodeInfo
* untangled module loading logic between RecursiveLoad and isolate - that logic is encapsulated in EsIsolate and RecursiveModuleLoad, where isolate just consumes modules as they become available - does not require to pass Arc<Mutex<Isolate>> around anymore
* removed EsIsolate.mods_ in favor of Modules and moved them inside EsIsolate
* EsIsolate now requires "loader" argument during construction - struct that implements Loader trait
* rewrite first methods on isolate as async
