[mac/arm] fix clang/test/Driver/darwin-ld-dedup.c

The test needs an object file, which it currenty gets with
`-target x86_64-apple-darwin10`.  Rather than adding `REQUIRES: X86`, create
the object file via yaml2obj. This way, the test runs and passes even if the
host arch isn't x86 and only the host arch is built.

Part of PR46644.