Fixed message signing errors that clobbered critical Error properties (#3356).
Fixed message signing errors that clobbered critical Error properties (#3356).

ethers-io/ethers.js,ethers-io/ethers.js,ethers-io/ethers.js,ethers-io/ethers.js,ethers-io/ethers.js,ethers-io/ethers.js,ethers-io/ethers.js