macho: put dSYM bundle in zig-cache
macho: put dSYM bundle in zig-cache

Originally, I thought that the dSYM bundle has to reside side-by-side
with the binary it carries the debugging information for. However, it
turns out macOS is clever enough that it auto-searches for matching
dSYM bundle based on the embedded UUID of the binary.

To verify this, run this on your macOS:

```
mdfind "com_apple_xcode_dsym_uuids == <UUID from LC_UUID>"
```

See [here] for more info.

[here]: https://developer.apple.com/documentation/xcode/adding-identifiable-symbol-names-to-a-crash-report

andrewrk/zig,zig-lang/zig,andrewrk/zig,zig-lang/zig,zig-lang/zig