Revert "tflite: generate flatbuffers files from schema with flatc"

This reverts commit 05f5ebad.

Reason for revert: Likely the reason for https://ci.chromium.org/ui/p/chromium/builders/ci/Deterministic%20Linux%20(dbg)

The error file [1] has many mentions to tflite and this is the CL that touches it in the blame list.


[1]https://logs.chromium.org/logs/chromium/buildbucket/cr-buildbucket/8745482532584093729/+/u/compare_build_artifacts/stdout?format=raw

Original change's description:
> tflite: generate flatbuffers files from schema with flatc
>
> currently the generated flatbuffer files are checked-in to tensorflow source.
> this breaks builds with unbundled flatbuffers on any version mismatch,
> because flatc-generated headers have static_asserts checking if same version
> of library and flatc is used.
>
> Bug: https://github.com/tensorflow/tensorflow/issues/62298
> Change-Id: Ie4ed9b2683acdb850e35b3861fcfbc4828f536e7
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5595037


> Commit-Queue: Elly FJ <ellyjones@chromium.org>
> Reviewed-by: Sophie Chang <sophiechang@chromium.org>
> Reviewed-by: Elly FJ <ellyjones@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1312988}

Bug: https://github.com/tensorflow/tensorflow/issues/62298, b/346487323
Change-Id: I4557c15468796ef3b129ee5518cbb636da55141a
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5622171


Reviewed-by: Sophie Chang <sophiechang@chromium.org>
Reviewed-by: David Awogbemila <awogbemila@chromium.org>
Commit-Queue: Sophie Chang <sophiechang@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1313491}