Replace Hardhat with EDR in CI

[fvictorio]

The CI run's a subset of Hardhat tests, but we have migrated those tests to the EDR repo. This is still working because we also kept the old tests in the Hardhat repo, but we want to remove them. Before doing that though, we need to point solc's CI to the EDR repo.

I tested the steps locally with the latest soljson.js built by the CI, and it worked fine, but we won't know for sure until it actually runs in the CI.

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[cameel]

Thanks, looks good!

Note that we also run these tests in CI for solc-js: https://github.com/ethereum/solc-js/blob/master/.circleci/config.yml. So if you want to drop them, we need to update that as well.

Also, if cancun issues have been resolved, then we should try to re-enable these tests, which were disabled only due to this:

• solidity/.circleci/config.yml

  Lines 760 to 761 in 4ab3e36

  	# NOTE: test suite disabled due to dependence on a specific version of Hardhat
  	# which does not support shanghai EVM.

• solidity/.circleci/config.yml

  Lines 1922 to 1926 in 4ab3e36

  	# TODO: Dropping the external tests below since they are based on old forks and
  	# fail after update the default evm version to cancun.
  	#- t_ext: *job_native_compile_ext_trident
  	#- t_ext: *job_native_compile_ext_chainlink
  	#- t_ext: *job_native_compile_ext_bleeps

• solidity/.circleci/config.yml

  Lines 1945 to 1949 in 4ab3e36

  	# TODO: Dropping the external tests below since they are based on old forks and
  	# fail after update the default evm version to cancun.
  	#- t_native_compile_ext_trident
  	#- t_native_compile_ext_chainlink
  	#- t_native_compile_ext_bleeps

I'm still approving, since merging the PR even without these is an overall improvement.

[ekpyron]

Merged it for now - but we should look indeed also look into the other disabled tests and workarounds and see what we can remove now!

[alcuadrado]

Thanks for merging this! Franco is going to be OOO for a few weeks. Once he's back, we'll update the other repo and resolve the issues around disabled tests.

In the meantime, we won't delete any test from hardhat's repository.