Prerequiste changes to export mv3/mv2 targetting CMSIS-NN backend

[psiddh]

Summary

This PR correctly identifies that ConvertToCortexMPass inherits from XNNPACKPass and properly passes it the exported_program() argument:

• ReplaceQuantNodesPass → issubclass(XNNPACKPass) = False → instantiated as pass_cls()
• ConvertToCortexMPass → issubclass(XNNPACKPass) = True → instantiated as pass_cls(exported_program()) ✓
• QuantizedOpFusionPass → issubclass(XNNPACKPass) = False → instantiated as pass_cls()

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Test plan

python3 -m examples.arm.aot_arm_compiler -m mv2 --target=ethos-u55-128 --quantize --enable_qdq_fusion_pass --output=./output/mv2_cmsis

Without this change, the error would be
File "/home/sidart/executorch/examples/arm/aot_arm_compiler.py", line 808, in transform_for_cortex_m_backend
else pass_cls()
TypeError: XNNPACKPass.init() missing 1 required positional argument: 'exported_program'"

[pytorch-bot]

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❌ 1 New Failure, 1 Cancelled Job, 1 Unrelated Failure

As of commit 6fc9d49 with merge base d4ce813 ():

NEW FAILURE - The following job has failed:

• Lint / lintrunner / linux-job (gh)
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• pull / unittest-editable / macos / macos-job (gh)
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• pull / android / run-emulator (gh) (#16137)
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