Build warnings in Node 14

[jason0x43]

When building Intern 4.x or 5 under Node 14, many circular dependency warnings will be displayed:

(node:87088) Warning: Accessing non-existent property 'column' of module exports inside circular dependency
(node:87088) Warning: Accessing non-existent property 'filename' of module exports inside circular dependency
(node:87088) Warning: Accessing non-existent property 'lineno' of module exports inside circular dependency
(node:87088) Warning: Accessing non-existent property 'column' of module exports inside circular dependency
(node:87088) Warning: Accessing non-existent property 'filename' of module exports inside circular dependency

These don't affect the build process, they're just annoying. They also don't affect Intern when used as a library, only the Intern build process.

The culprits appear to be shelljs and stylus. Shelljs fixes the issue in v0.8.4. Stylus doesn't yet have a fix.

[jason0x43]

See https://github.com/stylus/stylus/issues/2534, https://github.com/shelljs/shelljs/issues/991

[jason0x43]

Partially addressed in 64e305d6

[sunderla]

This issue has been resolved for stylus 0.54.8 and does not display these errors anymore. See #2538. This issue can be closed.