refactor(tvix/cli/default.nix): make eval tests and benches derivations r/7989

This makes the eval tests and benchmarks standalone Nix derivations and
readTree targets:

```
nix-build -A tvix.cli.eval-nixpkgs-cross-hello-outpath
nix-build -A tvix.cli.benchmark-nixpkgs-attrnames
```

Even without doing any fetches, We need to set `SSL_CERT_FILE`, so
reqwest is able to load its CA roots.

Change-Id: Ib45282d01044165c7816391adbeeb26334f8e924
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11493
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI
Autosubmit: flokli <flokli@flokli.de>

0 files changed, 0 insertions, 0 deletions