Avoid creating a new array inside doResolve.

[gdborton]

This is a minor optimization that avoids allocating immediately dereferenced arrays when creating a new stack inside doResolve. In the build that I'm testing against, this is called >750k times, which means that we're allocating ~32mb of array data to the heap that's then spent in GC.

It's hard to find optimizations in webpack's codebase, but from my debugging we're spending more time in GC than in any other function.

Here's a jsperf comparing these two ways of creating a one item set:
https://jsperf.app/vureri

And a screenshot of the output for me:

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.99%. Comparing base (1213f32) to head (a10531a).
Report is 6 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #427   +/-   ##
=======================================
  Coverage   91.99%   91.99%           
=======================================
  Files          44       44           
  Lines        2123     2124    +1     
  Branches      645      645           
=======================================
+ Hits         1953     1954    +1     
  Misses        138      138           
  Partials       32       32           

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[alexander-akait]

Thank you