Merge "If filter/filter_out pattern is a list, remove empty elements from it."...

Merge "If filter/filter_out pattern is a list, remove empty elements from it." am: fe93495f am: c3b087d7 am: 1697f494 am: 421693c8

Original change: https://android-review.googlesource.com/c/platform/build/+/1810525

Change-Id: If2f02e44816b6318f2a274f203c8eed9edaf1d05