This reverts commit fea5914c926e2f013a8b5e27eaa74c7047fb2c71.

This reverts commit 069e8bcd82c4420239f95c7e6a09e1f756317cfc.

Summary:
Some tests failing, revert this for now.

Summary:
Currently there are several layers to handle `printf`. Since we now have
varargs and an implementation of `printf` this can be heavily
simplified.

1. The frontend renames `printf` into `omp_vprintf` and gives it an
   argument buffer.

Removing 1. triggered some code in the AMDGPU backend menat for HIP /
OpenCL, so I hadded an exception to it.

2. Forward this to CUDA vprintf or ignore it.

We no longer need special handling for it since we have varargs. So now
we just forward this to CUDA vprintf if we have libc, otherwise just
leave `printf` as an external function and expect that `libc` will be
linked in.

Summary:
This patch implements the `printf` family of functions on the GPU using
the new variadic support. This patch adapts the old handling in the
`rpc_fprintf` placeholder, but adds an extra RPC call to get the size of
the buffer to copy. This prevents the GPU from needing to parse the
string. While it's theoretically possible for the pass to know the size
of the struct, it's prohibitively difficult to do while maintaining ABI
compatibility with NVIDIA's varargs.

Depends on https://github.com/llvm/llvm-project/pull/96015.

This is a part of #97655.

Reverts llvm/llvm-project#98075

bots are broken

This is a part of #97655.

Summary:
This patch adds a temporary implementation that uses a struct-based
interface in lieu of varargs support. Once varargs support exists we
will move this implementation to the "real" printf implementation.

Conceptually, this patch has the client copy over its format string and
arguments to the server. The server will then scan the format string
searching for any specifiers that are actually a string. If it is a
string then we will send the pointer back to the server to tell it to
copy it back. This copied value will then replace the pointer when the
final formatting is done.

This will require a built-in extension to the varargs support to get
access to the underlying struct. The varargs used on the GPU will simply
be a struct wrapped in a varargs ABI.