Revert "Make flatcc cross-compile deterministic (#4312)" (#4528)

Summary:
This reverts commit 15815dd5cd58b6d250dc98f8a4b121c77c44dbed, which broke the test-coreml-delegate job. Details in https://github.com/pytorch/executorch/pull/4312#issuecomment-2266207512

Pull Request resolved: https://github.com/pytorch/executorch/pull/4528

Reviewed By: cccclai

Differential Revision: D60696305

Pulled By: dbort

fbshipit-source-id: 12677330b31b9fa180b79ec9daa5eef05cfd48d7