Concurrent solc downloads fail

[roderik]

We use a NX (nx.dev) mono repo setup where we run tests, typechain builds, etc concurrently for a bunch of hardhat projects. When it decides to run any of these tasks for more than one project, it fails with the following error

There was an unexpected problem downloading the compiler: ENOENT: no such file or directory, open '/home/runner/.cache/hardhat-nodejs/compilers/linux-amd64/solc-linux-amd64-v0.8.4+commit.c7e474f2'
41

One of the other ones will work and all the rest also since the cache file is there.

[fvictorio]

@roderik do you think you could make a minimal reproduction example that triggers this issue? Even if the reproduction steps include "run this command 100 times and 1 of those will fail".