fix(NormNum): stop after a location closes the goal

[sankalpsthakur]

norm_num at h1 h2 ... (and other tactics built on Lean.Elab.Tactic.withNondepPropLocation) unconditionally processed every hypothesis in the location list, then the target. If an earlier hypothesis closed the goal (e.g. norm_num found h1 to already be False), processing continued against an already-closed goal instead of stopping.

Stops iterating once getGoals is empty.

Motivated by #28703.

Validation

• Built locally: lake build Mathlib.Util.AtLocation and lake build MathlibTest.Tactic.NormNum.Basic — both succeed, including the added regression test (h : 0 = 1, h2 : 0 = 2 case).
• Scope note: withNondepPropLocation currently has no other callers in the Mathlib tree besides its own definition file, so the change is narrowly scoped to norm_num's own location handling. Did not run a full-library build; relying on CI for broader coverage.

Closes #28703

AI/LLM disclosure

AI coding tools were used to help draft this change and PR description. I reviewed the complete change, understand the reasoning, and verified the build locally before submitting.

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PR summary 3a7767a7e2

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 3a7767a).

• +0 new declarations
• −0 removed declarations

No declaration differences.

---

No changes to strong technical debt.

No changes to weak technical debt.

Current commit 3a7767a7e2
Reference commit 54df8a3f96

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).