[3.2] skip context free actions during light validation

[ClaytonCalabrese]

Skip context_free_action execution during light validation.
Since context free actions are designed not have any side-effects (except for possible console output) and to only influence execution via asserting, the fact that they exist in a signed block is indication that the producer executed them and they didn't assert. Therefore, they can be skipped during light validation where producers are implicitly trusted.
Any node that wishes to include all context free action console output in action traces needs to run with --force-all-checks for replay, run with no trusted producers, and run in full validation mode. NOTE: this is currently not completely accurate as it depends on PR Skip checks [ #8848]

Part of #188

Backports EOSIO/eos#8846
Resolves: #556

[ClaytonCalabrese]

Resolves: #556