Add filegroup support to notice property.

Also, replace all notice file references with the parent directory
pattern(../) with filegroups. This new version has
ALLOW_MISSING_DEPENDENCIES support, so shouldn't break branches that
don't contain the libwinpthread project.

Bug: 118899640
Test: Manual build + forrest runs on previously failed branches.
Change-Id: I13e70e8dab547f82c1c8f15eccc7ae116e480ad5