[llvm] [llvm] Replace `OwningArrayRef` with `std::vector` in `BTFParser` (PR #169124)

[Jeremy Morse via llvm-commits]

https://github.com/jmorse commented:

This seems fine; could we use SmallVector instead, to avoid allocating memory for small problem sizes? (Depends on the workload of course).

https://github.com/llvm/llvm-project/pull/169124