[recipes] Isolate build outputs with no subdirs

Bug: skia:6473
Change-Id: If243b6afb748529d2bdb212e360cd4338edc929c
Reviewed-on: https://skia-review.googlesource.com/130942
Reviewed-by: Ben Wagner <benjaminwagner@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
135 files changed