fix(testing/bench.py): add float16 and float8_e5m2 to dtype_to_str mapping

[pandacooming]

Summary

Add the two missing dtype mappings to dtype_to_str() in tile_kernels/testing/bench.py:

• torch.float16 → 'fp16'
• torch.float8_e5m2 → 'e5m2'

Fixes #4

Changes

def dtype_to_str(dtype: torch.dtype) -> str:
    mapping = {
        torch.float32: 'fp32',
+       torch.float16: 'fp16',
        torch.bfloat16: 'bf16',
        torch.float8_e4m3fn: 'e4m3',
+       torch.float8_e5m2: 'e5m2',
        torch.int8: 'e2m1',
    }
    if dtype not in mapping:
-       raise ValueError(f'Unsupported dtype: {dtype}. Only fp32, bf16, e4m3, and int8(e2m1) are supported')
+       raise ValueError(f'Unsupported dtype: {dtype}. Only fp32, fp16, bf16, e4m3, e5m2, and int8(e2m1) are supported')
    return mapping[dtype]

Testing

All 6 supported dtypes pass and invalid dtype still raises ValueError:

torch.float16: ✅
torch.float32: ✅
torch.bfloat16: ✅
torch.float8_e4m3fn: ✅
torch.float8_e5m2: ✅
torch.int8: ✅
int32: ✅ raises ValueError