ASAN and Fuzzer are currently broken

[alexreinking]

The wheels built by https://github.com/halide/llvm-wheel lack the compiler symlinks to save on wheel size. But this broke the ASAN and Fuzzer configurations that depended on those. We can either figure out a way to restore the links (a wrapper script? some self-replacing thing that Andrew suggested?) or update the configuration here to work around it (restores functionality sooner at the expense of configuration complexity).