Reduce number of HDNode testcases so CI does not timeout.
Reduce number of HDNode testcases so CI does not timeout.

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