Importing @eth-optimism/plugins/hardhat/ethers breaks source map support

[krzkaczor]

Describe the bug
import '@eth-optimism/plugins/hardhat/ethers'
breaks source map supports (line numbers are off).

This is because importing ganache-core which imports source-map-support/register.

A related issue in hardhat/waffle: TrueFiEng/Waffle#281

Quick workaround: (for end-users of this lib)
source-map-support is able to ąvoid re-registering if one particular version is registered multiple times so a reasonable workaround is to force install only one particular version. To do this add in package.json:

"resolutions": {
    "source-map-support": "0.5.19"
  }

Solution:

1. Help me with: Fix sourcemap support once and for all trufflesuite/ganache#879

[smartcontracts]

Glad that trufflesuite/ganache#879 seems to be getting resolved. We're likely going to remove all ethereumjs-vm functionality from this repository and prefer using geth directly, which should fix the issue if not immediately fixed in ganache-core.

[gakonst]

This is the PR which removes ethereumjs-vm: #31

[smartcontracts]

Closing this since we no longer use ethereumjs-vm under the hood (at least for now). Let me know if you need any other help!!