cmd/link: accept extra blocks in TestFallocate
cmd/link: accept extra blocks in TestFallocate

For #41127

Change-Id: I794a082299c6dce4202223197ece1864bed36810
Reviewed-on: https://go-review.googlesource.com/c/go/+/282555
Trust: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
Reviewed-by: Austin Clements <7ea35d812706d9213868749011af1ed4fa2f6aa0@google.com>

CAFxX/go,golang/go,cloudflare/go,nawawi/go,CAFxX/go,nawawi/go,CAFxX/go,CAFxX/go,nawawi/go,nawawi/go,cloudflare/go,golang/go,cloudflare/go,CAFxX/go,nawawi/go,nawawi/go,CAFxX/go,golang/go,golang/go,CAFxX/go,cloudflare/go,golang/go,nawawi/go,cloudflare/go,golang/go,cloudflare/go,nawawi/go,cloudflare/go,CAFxX/go,golang/go,cloudflare/go,golang/go