llvmPackages_15.llvm: fix the tests on `x86_64-darwin`

Details within but ultimately there isn't a satisfying resolution for
any of the three test failures we were seeing and all three deserve
further exploration.

For the `sw_vers` macOS version issue in particular, it's possible to
observe the nixpkgs provided `CoreFoundation` vs system `CoreFoundation`
for `x86_64` and `aarch64` like so (on a host running macOS `13.0.1`):

```console
$ nix-shell -p darwin.DarwinTools --system aarch64-darwin --command "sw_vers"
ProductName:    macOS
ProductVersion: 13.0.1
BuildVersion:   22A400

$ nix-shell -p darwin.DarwinTools --system x86_64-darwin --command "sw_vers"
ProductName:    Mac OS X
ProductVersion: 10.16
BuildVersion:   22A400
```

Where `/System/Library/CoreServices/SystemVersion.plist` has:
```console
$ cat /System/Library/CoreServices/SystemVersion.plist | grep ProductVersion
-A 1
	<key>ProductVersion</key>
	<string>13.0.1</string>
```

Further:
```console
$ nix-shell -p darwin.DarwinTools --system aarch64-darwin --command 'otool -L $(which sw_vers)'
/nix/store/nb2q33ak2zif49ndcpc6m823z0vhmy8y-DarwinTools-1/bin/sw_vers:
	/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation (compatibility version 150.0.0, current version 1770.255.0)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1292.60.1)

$ nix-shell -p darwin.DarwinTools --system x86_64-darwin --command 'otool -L $(which sw_vers)'
/nix/store/88v4kjvgwl71byfpvd0baviiq7l5appc-DarwinTools-1/bin/sw_vers:
	@rpath/CoreFoundation.framework/Versions/A/CoreFoundation (compatibility version 150.0.0, current version 1454.90.0)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1238.60.2)
```

For the `x86_64` `sw_vers` binary we can see rpath:
```console
$ nix-shell -p darwin.DarwinTools --system x86_64-darwin --command 'otool -l $(which sw_vers)' | grep LC_RPATH -A 2 -B 1
Load command 13
          cmd LC_RPATH
      cmdsize 120
         path /nix/store/zvr4wypbgskhhw9cawfn7mmxfa75nh8f-swift-corefoundation-unstable-2018-09-14/Library/Frameworks (offset 12)
```

And we can confirm that the nixpkgs provided `CoreFoundation` is what
ultimately gets loaded:
```console
$ nix-shell -p darwin.DarwinTools --system x86_64-darwin --command 'DYLD_PRINT_LIBRARIES=1 sw_vers'
dyld[16215]: <no uuid> /nix/store/88v4kjvgwl71byfpvd0baviiq7l5appc-DarwinTools-1/bin/sw_vers
dyld[16215]: <no uuid> /nix/store/zvr4wypbgskhhw9cawfn7mmxfa75nh8f-swift-corefoundation-unstable-2018-09-14/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation
dyld[16215]: <no uuid> /nix/store/xd2a4xh8kdwq0j67hzgw720npdw5hzkk-ICU-66108/lib/libicucore.A.dylib
<snipped>
```

```bash
nix-diff \
    $(nix path-info nixpkgs#legacyPackages.aarch64-darwin.darwin.DarwinTools --derivation) \
    $(nix path-info nixpkgs#legacyPackages.x86_64-darwin.darwin.DarwinTools --derivation)
```
doesn't show any _obvious_ discrepancies

0 files changed, 0 insertions, 0 deletions