make extract_delegate_segments=True by default (#3405)

Summary:
Pull Request resolved: https://github.com/pytorch/executorch/pull/3405

updated all existing callsites to use the previous default value of False.

when extract_delegate_segments is set to False (previous behavior), the backend blob data is part of the flatbuffer serialized program. this leads to higher memory consumption, as backends may not need the input blob post initialization, but cannot free the memory as it's part of the flatbuffer.

when extract_delegate_segments is set to True, the backend blob data is extracted into separate segments. this way, each backend can choose to free the memory after initialization if it is no longer needed. this reduces peak memory consumption as a result. the con is that this leads to an increased program size due to internal padding between the flatbuffer program and the extracted segments

Reviewed By: JacobSzwejbka, cccclai, dbort, zonglinpengmeta

Differential Revision: D56712292

fbshipit-source-id: 0f29972357b3a8288f170ce4a00f0d7b043036e5