Revert "soong_zip: set local header crc for symlinks"

This reverts commit b88c4dfb.

This made it worse, now that the local header crc matches the global
header, unzip will attempt to unzip the symlink.  However, the local
header size is still incorrect, so it produces an empty file instead
of a symlink.

Bug: 110716403
Change-Id: Ifd9aabc04d180b7ead4aec8566c151206b6b7c57