InfoParserDynamic::parse() looks for strings in a file path without normalising

Problem/Motivation

🐛 "core_version_requirement key must be present" on core modules on Windows Needs review revealed that the logic in \Drupal\Core\Extension\InfoParserDynamic::parse() is fragile when Windows is involved.

Steps to reproduce

Proposed resolution

Either

• normalise the file paths
• provide an OS safe pathStartsWith method()
• don't accept absolute file paths

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet