[Merged by Bors] - perf(Translate): use cache in guessReorder

[JovanGerb]

This PR fixes a performance issue in to_additive/to_dual. The guessReorder function did not use a cache, meaning that it would visit the same expressions multiple times unnecessarily.

---

[github-actions]

PR summary 97dd87c9f5

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference

---

Declarations diff (regex)

No declarations were harmed in the making of this PR! 🐙

You can run this locally as follows

## from your `mathlib4` directory:
git clone https://github.com/leanprover-community/mathlib-ci.git ../mathlib-ci

## summary with just the declaration names:
../mathlib-ci/scripts/pr_summary/declarations_diff.sh <optional_commit>

## more verbose report:
../mathlib-ci/scripts/pr_summary/declarations_diff.sh long <optional_commit>

The doc-module for scripts/pr_summary/declarations_diff.sh in the mathlib-ci repository contains some details about this script.

Declarations diff (Lean)

✅ Lean-aware diff — post-build, computed from the Lean environment (commit 97dd87c).

• +0 new declarations
• −0 removed declarations

No declaration differences.

---

No changes to strong technical debt.

No changes to weak technical debt.

Current commit 97dd87c9f5
Reference commit 463839dbb4

This script lives in the mathlib-ci repository. To run it locally, from your mathlib4 directory:

git clone https://github.com/leanprover-community/mathlib-ci.git ../mathlib-ci
../mathlib-ci/scripts/reporting/technical-debt-metrics.sh pr_summary

• The relative value is the weighted sum of the differences with weight given by the inverse of the current value of the statistic.
• The absolute value is the relative value divided by the total sum of the inverses of the current values (i.e. the weighted average of the differences).

[JovanGerb]

!radar

[leanprover-radar]

Benchmark results for 97dd87c against 463839d are in. There are significant results. @JovanGerb

• ✅ build//instructions: -109.4G (-0.07%)

Large changes (1✅)

• ✅ build/module/Mathlib.GroupTheory.GroupAction.SubMulAction.OfFixingSubgroup//instructions: -31.6G (-35.55%)

Small changes (1✅, 3🟥)

• 🟥 build/module/Mathlib.Algebra.Group.InjSurj//instructions: +376.4M (+2.50%)
• ✅ build/module/Mathlib.GroupTheory.QuotientGroup.Basic//instructions: -746.0M (-2.29%)
• 🟥 build/module/Mathlib.Tactic.Translate.Core//instructions: +2.2G (+5.94%)
• 🟥 build/module/Mathlib.Tactic.Translate.Reorder//instructions: +603.0M (+5.01%)

[bryangingechen]

Thanks!
bors r+

[mathlib-bors]

Pull request successfully merged into master.

Build succeeded:

• ci (staging) / Post-CI job
• ci (staging) / Test and lint
• ci (staging) / Build
• ci (staging) / Lint style
• ci (staging) / Post-Build Step

[plp127]

Whoops, looks like I forgot to hit "submit comments" on github! Well I guess it's a little late now since the PR's merged already, I'll still post this here.