Finish support for .other module type

[calvincestari]

PR 2 of 3 for #2034

This wraps up support for dependency managers that are not Swift Package Manager. The behaviour was already correct, the tests just needed a bit of refactoring and wider test coverage.

• Removed the import statement tests from both fragment and operation template tests and instead created ImportStatementTemplateTests that bring wider test coverage.
• Fixed a bug in the line-by-line comparison function that would invalidly pass tests when the expected value had more lines than the actual.

[calvincestari]

@AnthonyMDev d0a677f relaxes the error condition from #2194 (comment).