Clip small scales to fp16 min
Summary: When the FC output min max range is very small, we want to enforce a cutoff on the scale parameter to better generalize for future values that could fall beyond the original range.
Test Plan:
More analysis about the output distributions can be found in N425166
An example workflow using fp16 min clipping is f240972205
Reviewed By: jspark1105
Differential Revision: D25681249
fbshipit-source-id: c4dfbd3ee823886afed06e6c2eccfc29d612f7e6
