`debuginfo/pretty-std-collections.rs` test sometimes fails on macOS

[JohnTitor]

CI on macOS sometimes fails due to this failure:

failures:

---- [debuginfo-lldb] debuginfo/pretty-std-collections.rs stdout ----
NOTE: compiletest thinks it is using LLDB version 1200
NOTE: compiletest thinks it is using LLDB without native rust support

error: Error while running LLDB
stderr:
------------------------------------------
error: need to add support for DW_TAG_base_type '()' encoded with DW_ATE = 0x7, bit_size = 0
clang: CommandLine Error: Option 'h' registered more than once!
LLVM ERROR: inconsistency in registered CommandLine options

------------------------------------------

failures:
    [debuginfo-lldb] debuginfo/pretty-std-collections.rs

You can find the full log here: https://github.com/rust-lang-ci/rust/runs/1340649828
The failure occurs on #78501, #78489, and #78661 (at least).

[JohnTitor]

Oh, I just found the related Zulip topic: https://rust-lang.zulipchat.com/#narrow/stream/242791-t-infra/topic/apple-x86_64.20gha.20checks

[pietroalbini]

Please ping me if another failure happens again.