And move StreamingPropertyFiles as its subclass. We will need similar
PropertyFiles instance for non-A/B OTA as well (to expose the
offset/size for the METADATA entry).
Bug: 74210298
Test: python -m unittest test_ota_from_target_files
Test: Generate an A/B OTA. Check the generated property-files string.
Test: pylint --rcfile=pylintrc \
ota_from_target_files.py \
test_ota_from_target_files.py
Change-Id: If90d97f0b330749fd8a6cde2ed9d0d6cd6ea60a8
(cherry picked from commit 432f374a1701909ca324f8b047666614684568c0)
d3fc38a073