Support layer_norm for static runtime (#56444)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/56444
Added out version for layer_norm
Test Plan:
buck test caffe2/aten:math_kernel_test -- NativeLayerNorm
buck test caffe2/benchmarks/static_runtime:static_runtime_cpptest
Reviewed By: hlu1
Differential Revision: D27873846
fbshipit-source-id: 53ee9fec4ff9a4e78198b031e86b5afd013626dd
