Function bootstrap::test::prepare_cargo_test

fn prepare_cargo_test(
    cargo: impl Into<Command>,
    libtest_args: &[&str],
    crates: &[Interned<String>],
    primary_crate: &str,
    compiler: Compiler,
    target: TargetSelection,
    builder: &Builder<'_>
) -> Command

Given a cargo test subcommand, pass it the appropriate test flags given a builder.