fix test that relies on maxFeeRate which recently changed
fix test that relies on maxFeeRate which recently changed

Summary:
This test has been breaking ever since the maxFee was
increased to 1000000 (multiplied by 10). The test purposely hits the
ceiling and is therefore 10x greater than it should be.

Reviewers: ben, alex

Reviewed By: alex

Subscribers: ben

Differential Revision: https://phabricator.bitgo.com/D4916

BitGo/BitGoJS,BitGo/BitGoJS,BitGo/BitGoJS,BitGo/BitGoJS