This commit removes "compat" mode. We shipped support for "npm:" specifier
support in v1.25 and that is preferred way to interact with Node code that we
will iterate and improve upon.
Previously `jsxImportSource` was resolved relative to the config file
during graph building, and relative to the emitted module during
runtime.
This is now fixed so that the JSX import source is resolved relative to
the module both during graph building and at runtime.
