This commit integrates import map and "classic" resolutions in
the "--compat" mode when using ES modules; in effect
"http:", "https:" and "blob:" imports now work in compat mode.
The algorithm works as follows:
1. If there's an import map, try to resolve using it and if succeeded
return the specifier
2. Try to resolve using "Node ESM resolution", and if succeeded return
the specifier
3. Fall back to regular ESM resolution
