v1.24.0
CI: add LTO jobs with LLVM 16
ci: use LLVM 17.0 by default
CI: update actions to v4
Update actions/upload-artifacts to v4
CI: set read-all permissions
CI: switch to LTO=ON for LLVM-16 build
CI: convert LLVM 17 rebuild job to matrix job
ci: added rebuild LLVM 18 workflow
lit-tests: support ispc-opt and run lit-tests for *.ll