DAP: building system_other.img for retrofit devices

For dynamic partitions in retrofit devices, system partition will be
a logical partition but system_other is not. However, current
build system use the same settings (logical) for both system.img and
system_other.img, leading AVB unable to locate the footer from the end
of system_other partition.

This commit support building system_other.img with correct partition size
while building system.img as a dynamic image.

Bug: 123506156
Test: check there is "system_other_size=2952790016" in file
      $OUT/obj/PACKAGING/system_other_intermediates/system_other_image_info.txt
Test: build system_other.img, then
      `simg2img $OUT/system_other.img system_other.img.raw`, checks the
      raw image size.

Change-Id: I748320a7770c694d06f06f4a35bfceb622849aa8