[eth]: Improve optimization runs to 10000

[ali-behjati]

Now that the contract size is smaller we can increase the optimization runs again. This PR changes it to 10000. It changes contract size from 19.22KB to 21.16KB but saves more gas. Below is the snapshot difference:

testBenchmarkUpdatePriceFeedsIfNecessaryNotFresh() (gas: -24 (-0.014%)) 
testBenchmarkGetUpdateFee() (gas: -21 (-0.016%)) 
testBenchmarkGetEmaPrice() (gas: -18 (-0.071%)) 
testBenchmarkGetPrice() (gas: -30 (-0.128%)) 
testBenchmarkUpdatePriceFeedsIfNecessaryFresh() (gas: -801 (-0.212%)) 
testBenchmarkUpdatePriceFeedsFresh() (gas: -801 (-0.224%)) 
testBenchmarkParsePriceFeedUpdatesForTwoPriceFeed() (gas: -741 (-0.233%)) 
testBenchmarkUpdatePriceFeedsNotFresh() (gas: -741 (-0.235%)) 
testBenchmarkParsePriceFeedUpdatesForOnePriceFeed() (gas: -741 (-0.238%)) 
testBenchmarkParsePriceFeedUpdatesForOnePriceFeedNotWithinRange() (gas: -747 (-0.239%)) 

This PR also modifies a comment for a deprecated state variable.