Since we have large gas_limit transactions on mainnet, we need to be able to adjust gas limit for blocks up quickly for these transactions, and similarly reduce it back to the default afterwards.
/// Checks the gas limit for consistency between parent and self headers.
///
/// The maximum allowable difference between self and parent gas limits is determined by the
/// parent's gas limit divided by the elasticity multiplier (1024).
Since we have large gas_limit transactions on mainnet, we need to be able to adjust gas limit for blocks up quickly for these transactions, and similarly reduce it back to the default afterwards.