Revert "Reapply "Use an abbrev to reduce size of VALUE_GUID records in ThinLTO...

Revert "Reapply "Use an abbrev to reduce size of VALUE_GUID records in ThinLTO summaries" (#90610)" (#91194)

Reverts llvm/llvm-project#90692

Breaking PPC buildbots. The bots are not meant to test LLD, but are
running a test that is using an old version of LLD without the change
(so is incompatible). Revert until a fix is found.