Cycles: Switch to HIP SDK 6.4.2 on Windows

This also reverts 367d5b7eabd53229fb7e79465b4761e65e531741,
as the math flags workaround is no longer needed.

Fix #139796
Fix #138646
Fix #139071
Fix #139070

Ref #140278

Co-authored-by: Brecht Van Lommel <brecht@blender.org>
Pull Request: https://projects.blender.org/blender/blender/pulls/145311

intern/cycles/device/hiprt/device_impl.cpp

@@ -225,11 +225,6 @@ string HIPRTDevice::compile_kernel(const uint kernel_features, const char *name,
   options.append(
       "-Wno-parentheses-equality -Wno-unused-value -ffast-math -O3 -std=c++17 -D __HIPRT__");
   options.append(" --offload-arch=").append(arch.c_str());
-  if (hipNeedPreciseMath(arch)) {
-    options.append(
-        " -fhip-fp32-correctly-rounded-divide-sqrt -fno-gpu-approx-transcendentals "
-        "-fgpu-flush-denormals-to-zero -ffp-contract=off");
-  }
 #  ifdef WITH_NANOVDB
   options.append(" -D WITH_NANOVDB");
 #  endif