llvm-project

93d4b1f7 - Reapply "[llvm-jitlink] Use concurrent linking by default." with fixes. (#120958)

Reapply "[llvm-jitlink] Use concurrent linking by default." with fixes. (#120958) Reapplies commit edca1d9bad2 which was reverted in 34531cff638 while I investigated bot failures, (e.g. https://lab.llvm.org/buildbot/#/builders/137/builds/10791). Commit 158a60051d2 should address the -check failures on the bots, which were caused by checks running earlier under the concurrent linking scheme before all files referenced by the checks had been fully linked. This patch also fixes the -threads option failure by renaming the option to -num-threads to avoid clashing with the ThreadCount cl::opt variable defined in ThinLTOCodeGenerator.cpp.