core: fix call to post-validation evm message hook

[protolambda]

Description

The post-validation check was running even when the EVM aborted without returning an execution-result. E.g. this may happen during block-building, when a tx does not pass state-transition pre-checks, and inclusion is aborted.

This post-validation hook was only set when the experimental Interop fork functionality is enabled, and thus not a production issue for mainnet.

Tests

E2E tests hit block-building code-path, although with flakes. I'll look into regression-testing it, but creating a more deliberate version of it e.g. with an action-test might mean it ignores the tx before even running the pre-checks.

Additional context

Reported by @mslipper, example in: https://app.circleci.com/pipelines/github/ethereum-optimism/optimism/72874/workflows/2ec0d66a-c736-4e19-ad98-031fb11428db/jobs/2986089/steps

[protolambda]

Hit an unrelated flake in the test-run of the fix. It was a small test fix, so I'm including it here in this PR. The tx that was being checked for rejection wasn't always making it into the tx-pool quick enough for consideration during block-building. That was fixed by making the tx-pool insertion synchronous for this one tx.