haiku/librustc_back: Remove incorrect no_integrated_as

[kallisti5]

• Makes rust bootstrap incorrectly search for xxx.s vs xxx.0.s
• Not needed or incorrect fix for another issue.

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @nikomatsakis (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

Please see the contribution instructions for more information.

[eddyb]

Please open an issue about the bug this triggers.

@bors r+ rollup

[bors]

📌 Commit 6ca124b has been approved by eddyb

[eddyb]

cc @michaelwoerister In case the bug is obvious.