Create a minimal_executor_runner target

[kirklandsign]

🚀 The feature, motivation and pitch

Currently our executor_runner is under examples/portable, but it's not really portable.

These deps are not portable.

executorch/examples/portable/executor_runner/executor_runner.cpp

Lines 24 to 28 in 4873681

	#include <gflags/gflags.h>
	#include <executorch/extension/data_loader/file_data_loader.h>
	#include <executorch/extension/evalue_util/print_evalue.h>
	#include <executorch/extension/runner_util/inputs.h>

How about let's create a minimal_executor_runner, with runtime/core and portable libs only, and get rid of extensions/, specifically

• no malloc
• no syscalls; make an interface for syscalls, like open(), read(), write()
• ideally no libc, libc++, or link to a static libc

This could prove that executorch can be really portable.

Alternatives

No response

Additional context

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RFC (Optional)

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cc @larryliu0820 @JacobSzwejbka @lucylq @jathu

[JacobSzwejbka]

https://github.com/pytorch/executorch/blob/main/test/size_test.cpp @kirklandsign

[JacobSzwejbka]

can switch to buffer data loader