PyTorch for WebGPU

Oddly, two tests fail for me with Brave (Version 1.51.118 / Chromium: 113.0.5672.126 (arm64)) on macOS Ventura 13.3.1

- pow([0], [0]) gradient, with "Expected «-Infinity» to be close to «0» (diff: < 0.0000005)"

- xlogy([0], [0.30000001192092896]) gradient with "Expected «0» to be close to «-1.2039728164672852»"

>>activa+S4
Same with Chrome 113.0.5672.92 (arm64) on Ventura 13.2.

Safari 16.3 has 4 failures: "webgpu is supported", "tensor is webgpu", "xlogy([0], [0]) gradient", "xlogy([0], [0.30000001192092896]) gradient"

zlacker