Add meta for aten.poisson

Based on upstream commit pytorch@38f97ec

Change-Id: I02ea48166ba96cf0c3ea841fa323e17b630fab08

Author: internal developer

torch/_meta_registrations.py

@@ -2044,6 +2044,12 @@ def meta_bernoulli_p(self, p=0.5, generator=None):
     return torch.empty_like(self).contiguous()
 
 
+@register_meta([aten.poisson.default, aten.poisson.out])
+@out_wrapper()
+def meta_poisson(self, generator=None):
+    return torch.empty_like(self)
+
+
 @register_meta(aten._fused_moving_avg_obs_fq_helper.default)
 def meta__fused_moving_avg_obs_fq_helper(
     self,