fix: don't consider &mut x as a last use in a call if x is used in another argument

[asterite]

Problem Resolved

Resolves https://github.com/noir-lang/noir-claude/issues/1553
Resolves https://github.com/noir-lang/noir-claude/issues/1563

Summary of Changes

This fixes a real bug where passing &mut x, x to a call didn't produce a clone on x so a mutation via &mut x (in the called method) ended up affecting x. That said, this is unlikely to happen in real code as there's probably no use in passing the same variable both as a mutable reference and as itself.

Then, a fix to rc_invariant had to be done to account for this case. This is a check that runs in debug builds.

User Documentation

Check one:

• No user documentation needed.
• Documented in docs/.
• [For Experimental Features] Documentation tracking issue created:

PR Checklist

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.

[github-actions]

Changes to Brillig bytecode sizes

Generated at commit: 2033ac4d3bb0e45bfb1567e44770c07ad726b13c, compared to commit: 54386dfcd6449707ec737e416d90825c0872e96b

🧾 Summary (10% most significant diffs)

Program	Brillig opcodes (+/-)	%
array_sort_inliner_max	+3 ❌	+0.74%
array_sort_inliner_min	+3 ❌	+0.74%
array_sort_inliner_zero	+3 ❌	+0.74%

---

Full diff report 👇

Program	Brillig opcodes (+/-)	%
array_sort_inliner_max	408 (+3)	+0.74%
array_sort_inliner_min	408 (+3)	+0.74%
array_sort_inliner_zero	408 (+3)	+0.74%
uhashmap_inliner_zero	7,150 (+18)	+0.25%
uhashmap_inliner_min	7,326 (+18)	+0.25%
uhashmap_inliner_max	9,152 (+18)	+0.20%

[github-actions]

Changes to number of Brillig opcodes executed

Generated at commit: 2033ac4d3bb0e45bfb1567e44770c07ad726b13c, compared to commit: 54386dfcd6449707ec737e416d90825c0872e96b

🧾 Summary (10% most significant diffs)

Program	Brillig opcodes (+/-)	%
array_sort_inliner_max	+3 ❌	+0.36%
array_sort_inliner_min	+3 ❌	+0.36%
array_sort_inliner_zero	+3 ❌	+0.36%

---

Full diff report 👇

Program	Brillig opcodes (+/-)	%
array_sort_inliner_max	843 (+3)	+0.36%
array_sort_inliner_min	843 (+3)	+0.36%
array_sort_inliner_zero	843 (+3)	+0.36%
uhashmap_inliner_max	68,560 (+18)	+0.03%
uhashmap_inliner_min	87,103 (+18)	+0.02%
uhashmap_inliner_zero	87,194 (+18)	+0.02%