Don't clone the metric if there's no remote writes.
Don't clone the metric if there's no remote writes.

The metric clone can't be further optimised, and is a
non-trivial memory allocation cost so fast path it
if there's no remote writes configured.

gottwald/prometheus,GoogleCloudPlatform/prometheus,agaoglu/prometheus,tomwilkie/prometheus,kangwoo/prometheus,agaoglu/prometheus,dsymonds/prometheus,tomwilkie/prometheus,Stackdriver/stackdriver-prometheus,GoogleCloudPlatform/prometheus,brancz/prometheus,yanghongkjxy/prometheus,gottwald/prometheus,tomwilkie/prometheus,keegancsmith/prometheus,Stackdriver/stackdriver-prometheus,gottwald/prometheus,Gouthamve/prometheus,alileza/prometheus,Gouthamve/prometheus,brancz/prometheus,AlekSi/prometheus,AlekSi/prometheus,Conorbro/prometheus,dsymonds/prometheus,JavierZunzunegui/prometheus,keegancsmith/prometheus,Conorbro/prometheus,Conorbro/prometheus,prometheus/prometheus,Colstuwjx/prometheus,Colstuwjx/prometheus,kangwoo/prometheus,JavierZunzunegui/prometheus,keegancsmith/prometheus,SaltedMan/prometheus-annotated,kzittritsch/prometheus,keegancsmith/prometheus,yanghongkjxy/prometheus,kzittritsch/prometheus,alileza/prometheus,SaltedMan/prometheus-annotated,slok/prometheus,alileza/prometheus,brancz/prometheus,Conorbro/prometheus,Colstuwjx/prometheus,SaltedMan/prometheus-annotated,Stackdriver/stackdriver-prometheus,dsymonds/prometheus,JavierZunzunegui/prometheus,slok/prometheus,Gouthamve/prometheus,dsymonds/prometheus,Colstuwjx/prometheus,prometheus/prometheus,kzittritsch/prometheus,kzittritsch/prometheus,amorken/prometheus,tomwilkie/prometheus,JavierZunzunegui/prometheus,agaoglu/prometheus,alileza/prometheus,slok/prometheus,amorken/prometheus,slok/prometheus,yanghongkjxy/prometheus,GoogleCloudPlatform/prometheus,kangwoo/prometheus,AlekSi/prometheus,yanghongkjxy/prometheus,keegancsmith/prometheus,agaoglu/prometheus,prometheus/prometheus,amorken/prometheus,prometheus/prometheus,brancz/prometheus,GoogleCloudPlatform/prometheus,gottwald/prometheus,alileza/prometheus,Gouthamve/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,SaltedMan/prometheus-annotated,Stackdriver/stackdriver-prometheus,amorken/prometheus,AlekSi/prometheus,kangwoo/prometheus