[cmake] Disable debug print with generator expression for Xcode (#11743)

This fixes the following error when configuring CMake with `-G Xcode`

```
CMake Error at build_tools/cmake/iree_cc_library.cmake:333 (file):
  Error evaluating generator expression:

    $<TARGET_OBJECTS:iree_runtime_impl.objects>

  The evaluation of the TARGET_OBJECTS generator expression is only suitable
  for consumption by CMake (limited under Xcode with multiple architectures).
  It is not suitable for writing out elsewhere.
```

With it, now we can use the `Xcode` generator for CMake.