Do not use -inf in boolean masks?

[justinchuby]

Should we set

onnxscript/onnxscript/function_libs/torch_lib/ops/nn.py

Line 2141 in a70ee8d

neg_inf = op.Constant(value=ir.tensor(-float("inf"), dtype=query.dtype))

to use float.lowest()?

Ref: microsoft/onnxruntime#25966 (review)