fix[cartesian]: While loops inside conditions

[romanc]

Description

This is a follow-up from PR #1630. It combines two things

1. In oir_to_npir, we fix conditional while loops in numpy backend. After PR 1630 these were stuck under certain conditions. Tests coverage extended.
2. In gtir_to_oir, we cleaned up the now unused mask parameter, which was pre-PR 1630 needed to pass down the mask information. With PR 1630 we actually removed the need for that parameter to be passed along because we properly nest the nested statements.

Requirements

• All fixes and/or new features come with corresponding tests.
• Important design decisions have been documented in the approriate ADR inside the docs/development/ADRs/ folder.

If this PR contains code authored by new contributors please make sure:

• The PR contains an updated version of the AUTHORS.md file adding the names of all the new contributors.

[romanc]

/cc @FlorianDeconinck, @twicki feel free to review and/or suggest additional test coverage

[FlorianDeconinck]

LGTM

This comes because the OIR was writing itself as a vector-logic IR (presumably to follow numpy implementation). But now, conditions are properly nested and the vector-way of masking per operation is left to NPIR

[romanc]

@egparedes Enrique would you have time to kick off the CSCS test suite and to do another review? Thanks in advance 🙏

[romanc]

@twicki please review

[egparedes]

cscs-ci run

[twicki]

LGTM,

This removes the extra code that was around combining masks that should now no longer be needed because nesting happens directly.

[romanc]

Thanks everybody for their reviews. @egparedes we are happy to merge now whenever is convenient for you.