Fix FA tutorial

[zhanglx13]

• Check correctness for fp8 inputs only when torch supports it
• Only run benchmark in fp16

[xiaohuguo2023]

passed on my test on MI250: collected 28 items Running 28 items in this shard: tutorials/06-fused-attention.py::test_op_fwd[False-4-48-1024-64-fp16], tutorials/06-fused-attention.py::test_op_fwd[False-4-48-1024-64-fp8], tutorials/06-fused-attention.py::test_op_fwd[False-4-48-2048-64-fp16], tutorials/06-fused-attention.py::test_op_fwd[False-4-48-2048-64-fp8], tutorials/06-fused-attention.py::test_op_fwd[False-4-48-4096-64-fp16], tutorials/06-fused-attention.py::test_op_fwd[False-4-48-4096-64-fp8], tutorials/06-fused-attention.py::test_op_fwd[False-4-48-1024-128-fp16], tutorials/06-fused-attention.py::test_op_fwd[False-4-48-1024-128-fp8], tutorials/06-fused-attention.py::test_op_fwd[False-4-48-2048-128-fp16], tutorials/06-fused-attention.py::test_op_fwd[False-4-48-2048-128-fp8], tutorials/06-fused-attention.py::test_op_fwd[False-4-48-4096-128-fp16], tutorials/06-fused-attention.py::test_op_fwd[False-4-48-4096-128-fp8], tutorials/06-fused-attention.py::test_op_fwd[True-4-48-1024-64-fp16], tutorials/06-fused-attention.py::test_op_fwd[True-4-48-1024-64-fp8], tutorials/06-fused-attention.py::test_op_fwd[True-4-48-2048-64-fp16], tutorials/06-fused-attention.py::test_op_fwd[True-4-48-2048-64-fp8], tutorials/06-fused-attention.py::test_op_fwd[True-4-48-4096-64-fp16], tutorials/06-fused-attention.py::test_op_fwd[True-4-48-4096-64-fp8], tutorials/06-fused-attention.py::test_op_fwd[True-4-48-1024-128-fp16], tutorials/06-fused-attention.py::test_op_fwd[True-4-48-1024-128-fp8], tutorials/06-fused-attention.py::test_op_fwd[True-4-48-2048-128-fp16], tutorials/06-fused-attention.py::test_op_fwd[True-4-48-2048-128-fp8], tutorials/06-fused-attention.py::test_op_fwd[True-4-48-4096-128-fp16], tutorials/06-fused-attention.py::test_op_fwd[True-4-48-4096-128-fp8], tutorials/06-fused-attention.py::test_op_bwd[4-48-1024-64], tutorials/06-fused-attention.py::test_op_bwd[4-48-2048-64], tutorials/06-fused-attention.py::test_op_bwd[4-48-4096-64], tutorials/06-fused-attention.py::test_op_bwd[1-16-8192-64]

06-fused-attention.py::test_op_fwd[False-4-48-1024-64-fp16] PASSED 06-fused-attention.py::test_op_fwd[False-4-48-1024-64-fp8] SKIPPED 06-fused-attention.py::test_op_fwd[False-4-48-2048-64-fp16] PASSED 06-fused-attention.py::test_op_fwd[False-4-48-2048-64-fp8] SKIPPED 06-fused-attention.py::test_op_fwd[False-4-48-4096-64-fp16] PASSED 06-fused-attention.py::test_op_fwd[False-4-48-4096-64-fp8] SKIPPED 06-fused-attention.py::test_op_fwd[False-4-48-1024-128-fp16] PASSED 06-fused-attention.py::test_op_fwd[False-4-48-1024-128-fp8] SKIPPED 06-fused-attention.py::test_op_fwd[False-4-48-2048-128-fp16] PASSED 06-fused-attention.py::test_op_fwd[False-4-48-2048-128-fp8] SKIPPED 06-fused-attention.py::test_op_fwd[False-4-48-4096-128-fp16] PASSED 06-fused-attention.py::test_op_fwd[False-4-48-4096-128-fp8] SKIPPED 06-fused-attention.py::test_op_fwd[True-4-48-1024-64-fp16] PASSED 06-fused-attention.py::test_op_fwd[True-4-48-1024-64-fp8] SKIPPED 06-fused-attention.py::test_op_fwd[True-4-48-2048-64-fp16] PASSED 06-fused-attention.py::test_op_fwd[True-4-48-2048-64-fp8] SKIPPED 06-fused-attention.py::test_op_fwd[True-4-48-4096-64-fp16] PASSED 06-fused-attention.py::test_op_fwd[True-4-48-4096-64-fp8] SKIPPED 06-fused-attention.py::test_op_fwd[True-4-48-1024-128-fp16] PASSED 06-fused-attention.py::test_op_fwd[True-4-48-1024-128-fp8] SKIPPED 06-fused-attention.py::test_op_fwd[True-4-48-2048-128-fp16] PASSED 06-fused-attention.py::test_op_fwd[True-4-48-2048-128-fp8] SKIPPED 06-fused-attention.py::test_op_fwd[True-4-48-4096-128-fp16] PASSED 06-fused-attention.py::test_op_fwd[True-4-48-4096-128-fp8] SKIPPED 06-fused-attention.py::test_op_bwd[4-48-1024-64] PASSED 06-fused-attention.py::test_op_bwd[4-48-2048-64] PASSED 06-fused-attention.py::test_op_bwd[4-48-4096-64] PASSED 06-fused-attention.py::test_op_bwd[1-16-8192-64] PASSED

================= 16 passed, 12 skipped in 340.48s (0:05:40) =================