Better handle symlinks in flattened APEXes in `art_apex_test.py`.

APEXes can contain symlinks which appear broken on host, as they may
reference files located under `/system` on device. For this reason,
avoid reading the size of a symlink's target present in a flattened
APEX in script `build/apex/art_apex_test.py`; instead, report the
length of the symlink's target's path as file size, like `ls`.

Test: art/build/apex/runtests.sh -l -t -s
Change-Id: I60dc53d94aa585e1ffa8633e775cb1a324ee5242
1 file changed