Block Gas Limit from contracts is not respected

[SurfingNerd]

known version: alpha4 commit 752d762

not to be confused with the block gas, that is respected. #31

see:

   /// Overrides the block gas limit. Whenever this returns `Some` for a header, the next block's gas limit must be
    /// exactly that value.
    fn gas_limit_override(&self, _header: &Header) -> Option<U256> {
        None
    }