Add fused triton kernel for swiglu (#8244)
**Performance**:
SwiGLU Benchmark
**Configuration:** `hidden=1024`, `dtype=bf16`
| Tokens | Variant | Forward (µs) | Forward + Backward (µs) | Backward
(µs) |
|-------:|:--------|-------------:|------------------------:|--------------:|
| 8,192 | `triton_fused` | 13.05 | 36.29 | 23.24 |
| 8,192 | `eager` | 22.53 | 61.47 | 38.94 |
| 16,384 | `triton_fused` | 26.25 | 67.65 | 41.40 |
| 16,384 | `eager` | 44.97 | 120.95 | 75.98 |
| 65,536 | `triton_fused` | 94.71 | 251.60 | 156.89 |
| 65,536 | `eager` | 163.12 | 444.64 | 281.52 |
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Signed-off-by: Hongwei Chen <hongweichen@microsoft.com>
