Support llvm dev releases

[trxcllnt]

This is a followup to https://github.com/nodejs/llnode/pull/389:

• Updates the range of LLVM versions we check (from 20, which is next dev version, to 99)
• Support downloading headers if the detected lldb version is the current dev release
  • i.e. doesn't have a release/XY.x branch, but does have a llvmorg-XY-init tag
• Update the PR action to test ubuntu-22.04 + LLVM versions up to current dev (v19)

If we wanted to be fancy, we could populate the supported versions and CI matrix by parsing git ls-remote --tags https://github.com/llvm/llvm-project.git 'refs/tags/llvmorg-*-init'.

Let me know if that's something you'd like me to add!

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 73.75%. Comparing base (de1f01d) to head (1d965d1).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #433      +/-   ##
==========================================
- Coverage   74.25%   73.75%   -0.51%     
==========================================
  Files          34       34              
  Lines        4999     5181     +182     
==========================================
+ Hits         3712     3821     +109     
- Misses       1287     1360      +73     

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