util.rs: fix "needless_borrow" errors

[cakebaker]

This PR fixes two "needless borrow" errors I introduced with #64

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 49.22%. Comparing base (933349e) to head (0a9d608).
Report is 3 commits behind head on main.

Files	Patch %	Lines
tests/common/util.rs	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #66      +/-   ##
==========================================
+ Coverage   43.73%   49.22%   +5.48%     
==========================================
  Files          18       18              
  Lines        2140     2200      +60     
  Branches      300      311      +11     
==========================================
+ Hits          936     1083     +147     
- Misses       1044     1078      +34     
+ Partials      160       39     -121     

Flag	Coverage Δ
macos_latest	48.65% <ø> (?)
ubuntu_latest	43.73% <ø> (ø)
windows_latest	0.11% <0.00%> (?)

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[cakebaker]

Closing this PR, the issue got fixed in #70