misc/cgo/test: avoid endless loop when we can't parse notes
misc/cgo/test: avoid endless loop when we can't parse notes

Change-Id: I780f6057d7b416d7b5c20a7906445dbaf2067d4e
Reviewed-on: https://go-review.googlesource.com/87416
Reviewed-by: Than McIntosh <4b2922593166fc595a9b1a408f34f5d3817fe9d2@google.com>

golang/gofrontend,golang/gofrontend,golang/gofrontend,golang/gofrontend