message: cg_clif: fix build with split dwarf
  This commit makes minor changes to the cranelift backend so that it can
  build given changes in cg_ssa for Split DWARF.
diff: @@ -75,6 +75,7 @@ fn emit_module(
  name,
  kind,
  object: Some(tmp_file),
  + dwarf_object: None,
  bytecode: None,
  },
  work_product,
  @@ -111,6 +112,7 @@ fn reuse_workproduct_for_cgu(
  name: cgu.name().to_string(),
  kind: ModuleKind::Regular,
  object,
  + dwarf_object: None,
  bytecode: None,
  }
  }
  @@ -290,6 +292,7 @@ pub(super) fn run_aot(
  name: metadata_cgu_name,
  kind: ModuleKind::Metadata,
  object: Some(tmp_file),
  + dwarf_object: None,
  bytecode: None,
  })
  } else {
  