feat(swc): sets filename property, so to make additional swc features…

[klassm]

Rollup Plugin Name: swc

This PR contains:

• [ ] bugfix
• [x] feature
• [ ] refactor
• [ ] documentation
• [ ] other

Are tests included?

• [ ] yes (bugfixes and features will not be merged without tests)
• [x] no

Breaking Changes?

• [ ] yes (breaking changes will not be merged unless absolutely necessary)
• [x] no

If yes, then include "BREAKING CHANGES:" in the first commit message body, followed by a description of what is breaking.

List any relevant issue numbers:

Description

Background: When using the swc rollup plugin in vitest, debugging will not work. I assume this comes from the filename property not being set, as the documentation states:

The filename is optional, but not all of Swc's
functionality is available when the filename is unknown, because a subset of options rely on the filename for their functionality.

Setting a filename should not have any side effects, just make debugging and other features work.

[klassm]

If someone has a hint on how to test that, I would also add a test. I've looked at the existing tests, but both file and sourceMap seem to be exactly the same after the change.

[tada5hi]

LGTM