This is a part of #97655.

Reverts llvm/llvm-project#98075

bots are broken

This is a part of #97655.

Summary:
These hacks can be removed now that
https://github.com/llvm/llvm-project/pull/83376 fixed the underlying
problem.

Summary:
The IEEE 754 standard as of the 2019 revision states that for fmin -0.0
is always less than 0.0 and for fmax 0.0 is always greater than 0.0.
These are currently not respected by the builtin value and thus cause
the tests to fail. This patch works around it in the implementation for
now by explicitly modifying the sign bit.

Summary:
The math directory likes to do architecture specific implementations of
these math functions. For the GPU case it was complicated by the fact
that both NVPTX and AMDGPU had to go through the same code paths. Since
reworking the GPU target this is no longer the case and we can simply
use the same scheme. This patch moves all the old code into two separate
directories. This likely results in a net increase in code, but it's
easier to reason with.