[Libomptarget] Add RPC-based `printf` implementation for OpenMP (#85638)

Summary:
This patch adds an implementation of `printf` that's provided by the GPU
C library runtime. This `pritnf` currently implemented using the same
wrapper handling that OpenMP sets up. This will be removed once we have
proper varargs support.

This `printf` differs from the one CUDA offers in that it is synchronous
and uses a finite size. Additionally we support pretty much every format
specifier except the `%n` option.

Depends on https://github.com/llvm/llvm-project/pull/85331