emscripten-releases macOS builds occasionally fails to upload with `Bad architecture in package`

See https://logs.chromium.org/logs/emscripten-releases/buildbucket/cr-buildbucket/8722411925976528753/+/u/Archive_Binaries__cross_/stdout

```
@@@BUILD_STEP Archive binaries@@@
Verifying architecture of MacOS binaries
/Volumes/Work/s/w/ir/x/w/install/bin/clang-21 is the wrong architecture:
subprocess.check_call(`file /Volumes/Work/s/w/ir/x/w/install/bin/clang-21`, cwd=`/Volumes/Work/s/w/ir/cache/builder/emscripten-releases/src`)
/Volumes/Work/s/w/ir/x/w/install/bin/clang-21: Mach-O 64-bit executable x86_64
Exception thrown in build step.
Traceback (most recent call last):
File "/Volumes/Work/s/w/ir/cache/builder/emscripten-releases/src/build.py", line 1454, in run
BuildRepos(build_targets)
File "/Volumes/Work/s/w/ir/cache/builder/emscripten-releases/src/build.py", line 1175, in BuildRepos
b.Run()
File "/Volumes/Work/s/w/ir/cache/builder/emscripten-releases/src/build.py", line 1112, in Run
self.runnable(*self.args, **self.kwargs)
File "/Volumes/Work/s/w/ir/cache/builder/emscripten-releases/src/build.py", line 1068, in ArchiveBinaries
VerifyMacArtifactsBuildArch(is_cross=is_cross)
File "/Volumes/Work/s/w/ir/cache/builder/emscripten-releases/src/build.py", line 1054, in VerifyMacArtifactsBuildArch
raise Exception('Bad architecture in package')
Exception: Bad architecture in package
```