default ice-ref to c-step (#4812)
Summary:
Pull Request resolved: https://github.com/pytorch/glow/pull/4812
if no compilation options are passed, default to c-step
fixed the FC and batchmatmul implementations to match C-step
fixed the fakelowp map calling to make sure we use the fp32 substitution of operators
updated the accumulator test to make it pass with fp32
Test Plan:
fakelowp tests
glow/test/numerics
net_runner
Reviewed By: jfix71
Differential Revision: D23086534
fbshipit-source-id: 3fbb8c4055bb190becb39ce8cdff6671f8558734
