Run zoomer profiling

Summary:
Pull Request resolved: https://github.com/facebookresearch/d2go/pull/518

Enable profiling for eval step only, not on every eval (which can be called during training)

Reviewed By: frabu6

Differential Revision: D44535915

fbshipit-source-id: 4497a3f74f5d751277df9ed41bc9bf21056341c4

d2go/runner/default_runner.py

@@ -385,6 +385,7 @@ class Detectron2GoRunner(D2GoDataAPIMixIn, BaseRunner):
             )
 
         attach_profilers(cfg, model)
+        if is_final:
             prepare_fb_model_for_eval(cfg, model)
 
         results = OrderedDict()