* [BugFix] Honor nan_propagate in reduce max/min/absmax clear=False write-back
MakeUpdate (the clear=False write-back merge) used plain Max/Min for
max/min/absmax reducers, silently dropping NaN when nan_propagate=True.
Now it emits max_nan/min_nan on fp16/bf16 when nan_propagate is set,
mirroring the existing MakeReduce path.
GHI: #2697
* [BugFix] Honor nan_propagate in reduce max/min/absmax clear=False write-back
MakeUpdate (the clear=False write-back merge) used plain Max/Min for
max/min/absmax reducers, silently dropping NaN when nan_propagate=True.
Now it emits max_nan/min_nan on fp16/bf16 when nan_propagate is set,
mirroring the existing MakeReduce path.
GHI: #2697