Refine dump-files

Dump $(modules_to_install) instead of $(product_target_FILES) to get a
more complete list of target files.

Use `echo $(modules_to_install) | tr -s ' ' '\n'` instead of
`$(foreach m,$(modules_to_install),$(info $(m)))`.
This way only one `echo` command is emitted instead of emitting `echo`
command for each file. This speeds up the invocation speed tremendously.

Bug: 159195410
Test: m dump-files
Change-Id: I06549cecc64177f1eb5a01e31a55d5eed307fcfd