macos-builder02 in particular has been having problems for a while now that no one could reproduce. We believe we have finally found the cause: missing shebangs, not just in the tests themselves but *also* in the inline scripts `nix-shell` itself writes. Fixes #1042. I believe this will also fix #1093. See also: https://github.com/NixOS/nix/pull/14778 Change-Id: I54d04a770b8e78484815db88a8bc88776a6a6964