Import maps don't take NPM modules

[andreespirela]

Bug report

Currently, NPM modules are not supported in import maps. It makes the runtime fail:

Import map:

{
  "imports": {
    "iseven": "npm:is-even"
  }
}

Code:

import isEven from "iseven"; 
globalThis.isTenEven = isEven(9);

Panic

thread 'deno_runtime::test::test_eszip_with_source_file' panicked at crates/base/src/deno_runtime.rs:491:30:\ncalled `Result::unwrap()` on an `Err` value: Relative import path \"iseven\" not prefixed with / or ./ or ../ f