Add LLVM 19 support

[laurynas-biveinis]

• Add missing template arguments to make_db_inode_reclaimable_ptr calls
• Suppress what appears to be false positive diagnostics about C-style casts
• Suppress -Wpedantic warning in TYPED_TEST_SUITE definition in Google Test
• include-what-you-use pragma tweaks
• Bump main GitHub Actions and CircleCI jobs to LLVM 19
• Add LLVM 18 to old-compilers.yml GitHub Action

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Please upload report for BASE (master@423f1cd). Learn more about missing BASE report.
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##             master     #595   +/-   ##
=========================================
  Coverage          ?   99.31%           
=========================================
  Files             ?       31           
  Lines             ?     3929           
  Branches          ?        0           
=========================================
  Hits              ?     3902           
  Misses            ?       27           
  Partials          ?        0           

Flag	Coverage Δ
Debug	99.31% <ø> (?)
Release	98.60% <ø> (?)

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.