Handle symlinks consistently in extract-from-apex.

Address missed comments on https://r.android.com/1314060.

Test: m installclean && m build-art-target-golem
  before and after CL, compare output of
  `sha1sum out/target/product/armv8/system/*/* | sort -k2`
Bug: 152255951
Change-Id: Id529f27bc458f85bf3dc2cedc276dea7e9fbfb09
1 file changed