resolc fails on deploy-only Yul objects

[xermicus]

resolc --yul fails when a Yul object has no _deployed sub-object, while solc compiles it fine.

object "Test" {
    code {
        { mstore(0, 42) return(0, 32) }
    }
}

__runtime is created unconditionally even when no runtime code exists, leaving its entry block without a terminator.