Move spack core commit forward

[scheibelp]

• Note: this should not merge until versioning scheme is updated according to Tag before/after spack core changes #1316

This moves the spack commit forward from Dec. 1 2025 to Mar. 27 2026 May 5 2026, in preparation for new hip-lang functionality (that will come from spack-packages, although is not available there yet, this commit in spack-core will be sufficient).

[michaelmckinsey1]

https://lc.llnl.gov/gitlab/benchpark/benchpark/-/pipelines/702231

I've manually checked this pipeline and don't see any new failures

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 64.26%. Comparing base (7db9c96) to head (74dd198).
⚠️ Report is 1 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #1318   +/-   ##
========================================
  Coverage    64.26%   64.26%           
========================================
  Files           49       49           
  Lines         3811     3811           
  Branches       338      338           
========================================
  Hits          2449     2449           
  Misses        1343     1343           
  Partials        19       19           

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[scheibelp]

(this is running into some issues with spack/spack#51957 - I will try to sort this out by end of Monday)