Auto merge of #128936 - bjorn3:fix_thin_archive_reading, r=jieyouxu

Support reading thin archives in ArArchiveBuilder

And switch to using ArArchiveBuilder with the LLVM backend too now that all regressions are fixed.

Fixes https://github.com/rust-lang/rust/issues/107407
Fixes https://github.com/rust-lang/rust/issues/107162
https://github.com/rust-lang/rust/issues/107495 has been fixed in a previous PR already.