fix: old aot_tools binaries do not work

[eseidel]

We try to execute them as dart scripts rather than running them
directly. While I was in here I cleaned up a typo and removed
fileName in favor of name.

Fixes #1644.

[eseidel]

I think I still need to add another test.

[codecov]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (162c0d7) 100.00% compared to head (4822126) 99.91%.
Report is 2 commits behind head on main.

❗ Current head 4822126 differs from pull request most recent head 1f62b2a. Consider uploading reports for the commit 1f62b2a to get more accurate results

Files	Patch %	Lines
packages/shorebird_cli/lib/src/cache.dart	82.60%	4 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##              main    #1645      +/-   ##
===========================================
- Coverage   100.00%   99.91%   -0.09%     
===========================================
  Files          156      156              
  Lines         4894     4911      +17     
===========================================
+ Hits          4894     4907      +13     
- Misses           0        4       +4     

Flag	Coverage Δ
shorebird_cli	99.89% <85.18%> (-0.11%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[felangel]

LGTM ✅