Update $PRODUCT_OUT from the soong system image files

When building a system image from 'android_system_image' module,
update the $PRODUCT_OUT files with the files installed to the system
image.
Soong updates the $PRODUCT_OUT files only if the android_system_image
module has "update_product_out: true" property.

Bug: 350599535
Test: lunch aosp_cf_x86_64_phone_soong_system-trunk_staging-userdebug
      && m
Test: adb sync
Change-Id: Ia3418c5380cac42d5c766e8304c8ed2bab3d835a