[CI] Reliability issues with lit timing file caching

[boomanaiden154]

https://github.com/llvm/llvm-project/actions/runs/18167747610/job/51714369096

Traceback (most recent call last):
  File "/home/gha/.local/lib/python3.12/site-packages/google/cloud/storage/blob.py", line 4401, in _prep_and_do_download
    self._do_download(
  File "/home/gha/.local/lib/python3.12/site-packages/google/cloud/storage/blob.py", line 1094, in _do_download
    response = download.consume(transport, timeout=timeout)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/gha/.local/lib/python3.12/site-packages/google/cloud/storage/_media/requests/download.py", line 280, in consume
    return _request_helpers.wait_and_retry(retriable_request, self._retry_strategy)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/gha/.local/lib/python3.12/site-packages/google/cloud/storage/_media/requests/_request_helpers.py", line 107, in wait_and_retry
    return func()
           ^^^^^^
  File "/home/gha/.local/lib/python3.12/site-packages/google/api_core/retry/retry_unary.py", line 294, in retry_wrapped_func
    return retry_target(
           ^^^^^^^^^^^^^
  File "/home/gha/.local/lib/python3.12/site-packages/google/api_core/retry/retry_unary.py", line 156, in retry_target
    next_sleep = _retry_error_helper(
                 ^^^^^^^^^^^^^^^^^^^^
  File "/home/gha/.local/lib/python3.12/site-packages/google/api_core/retry/retry_base.py", line 214, in _retry_error_helper
    raise final_exc from source_exc
  File "/home/gha/.local/lib/python3.12/site-packages/google/api_core/retry/retry_unary.py", line 147, in retry_target
    result = target()
             ^^^^^^^^
  File "/home/gha/.local/lib/python3.12/site-packages/google/cloud/storage/_media/requests/download.py", line 262, in retriable_request
    self._process_response(result)
  File "/home/gha/.local/lib/python3.12/site-packages/google/cloud/storage/_media/_download.py", line 232, in _process_response
    _helpers.require_status_code(
  File "/home/gha/.local/lib/python3.12/site-packages/google/cloud/storage/_media/_helpers.py", line 105, in require_status_code
    raise InvalidResponse(
google.cloud.storage.exceptions.InvalidResponse: ('Request failed with status code', 404, 'Expected one of', <HTTPStatus.OK: 200>, <HTTPStatus.PARTIAL_CONTENT: 206>)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/gha/actions-runner/_work/llvm-project/llvm-project/.ci/cache_lit_timing_files.py", line 75, in <module>
    download_timing_files(storage_client, bucket_name)
  File "/home/gha/actions-runner/_work/llvm-project/llvm-project/.ci/cache_lit_timing_files.py", line 63, in download_timing_files
    future.get()
  File "/usr/lib/python3.12/multiprocessing/pool.py", line 774, in get
    raise self._value
  File "/usr/lib/python3.12/multiprocessing/pool.py", line 125, in worker
    result = (True, func(*args, **kwds))
                    ^^^^^^^^^^^^^^^^^^^
  File "/home/gha/actions-runner/_work/llvm-project/llvm-project/.ci/cache_lit_timing_files.py", line 48, in _maybe_download_timing_file
    blob.download_to_filename(file_name)
  File "/home/gha/.local/lib/python3.12/site-packages/google/cloud/storage/blob.py", line 1403, in download_to_filename
    self._handle_filename_and_download(
  File "/home/gha/.local/lib/python3.12/site-packages/google/cloud/storage/blob.py", line 1276, in _handle_filename_and_download
    self._prep_and_do_download(
  File "/home/gha/.local/lib/python3.12/site-packages/google/cloud/storage/blob.py", line 4415, in _prep_and_do_download
    _raise_from_invalid_response(exc)
  File "/home/gha/.local/lib/python3.12/site-packages/google/cloud/storage/blob.py", line 4887, in _raise_from_invalid_response
    raise exceptions.from_http_status(response.status_code, message, response=response)
google.api_core.exceptions.NotFound: 404 GET https://storage.googleapis.com/download/storage/v1/b/llvm-premerge-cluster-us-central-object-cache-linux/o/lit_timing%2Fbuild%2Fruntimes%2Fruntimes-bins%2Fcompiler-rt%2Flib%2Fasan%2Ftests%2FX86_64LinuxConfig%2F.lit_test_times.txt?generation=1759332110900091&alt=media: No such object: llvm-premerge-cluster-us-central-object-cache-linux/lit_timing/build/runtimes/runtimes-bins/compiler-rt/lib/asan/tests/X86_64LinuxConfig/.lit_test_times.txt: ('Request failed with status code', 404, 'Expected one of', <HTTPStatus.OK: 200>, <HTTPStatus.PARTIAL_CONTENT: 206>)

We are not gracefully handling failures here for some reason when we should be.