-l option soong_zip can accept a file having space separated list

-l option of soong_zip is used to specify the list of input files that
should be zipped. However, it only accepted newline-separated list in the
file. This prevented us from using a rspfile as paths in rspfile are
space-separated in a single line. Fixing the problem by splitting the
file content by any unicode whitespace character including newline and
space.

Test: zip_test
Change-Id: Iba572109e30c01540eacf20bd2794ba60c870fa3