policy condition, avoid double initialization

[kapilt]

closes #6217


[kapilt]

would like to see a cli test here

[kkessels]

I checked out the branch with your changes and ran validate and run with same policy as mentioned in the issue. It seems this has solved the issue 👍

validate:

custodian.commands:INFO Configuration valid: /Users/kevinkessels/Projects/policies/policy.yaml

run:

custodian.commands:DEBUG Loaded file /Users/kevinkessels/Projects/policies/policy.yaml. Contains 1 policies
custodian.policy:INFO Skipping policy:cloudfunction due to execution conditions

[kapilt]

digging into this more while writing a test, the aws provider ends up creating a new policy instance when doing provider region initialization (auto filtering policies by region), which is why this didn't exhibit previously for the cli tests, other providers default to returning the previous policy instance, hence the double initialization error. leaning to just merging this as is, as we'll need to refactor the cli tests to enable reuse within the other providers test suites.