Currently, Zig semantically loads an array as a temporary when indexing
it. This means it cannot be guaranteed that only the requested element
is loaded; in particular, our self-hosted backends do not elide the load
of the full array, so this test case was crashing on self-hosted.
It's simpler and it takes advantage of
`std.Build.addAnonymousDependency`, which has a number of benefits,
including concurrenc and preventing extra zig-cache and zig-out
directories being created.
4 tests are ported over as an example.