Output only latest spatial layer if --alllayers 0

Right now, --alllayers 0 will only output operating points that exactly
match the largest one in the sequence header. However, in certain cases,
the largest one might not be available, and a smaller one should be
returned to the user instead.

This matches update_frame_buffers() in aomdec to output only the latest
frame if --alllayers 0 is specified.
26 jobs for fix020 in 7 minutes and 55 seconds (queued for 2 seconds)
latest
Status Job ID Name Coverage
  Style
passed #346381
amd64 debian
style-check

00:00:27

 
  Build
passed #346382
amd64 debian
build-debian

00:00:36

passed #346390
debian aarch64
build-debian-aarch64

00:01:11

passed #346391
debian aarch64
build-debian-aarch64-clang-5

00:00:56

passed #346394
debian armv7
build-debian-armv7

00:02:14

passed #346395
debian armv7
build-debian-armv7-clang-5

00:01:38

passed #346397
docker ppc64le
build-debian-ppc64le

00:01:19

passed #346383
amd64 debian
build-debian-static

00:00:42

passed #346393
debian aarch64
build-debian-werror

00:00:32

passed #346384
amd64 debian
build-debian32

00:00:39

passed #346392
macos
build-macos

00:00:35

passed #346396
amd64 debian
build-ubuntu-snap

00:00:41

passed #346388
amd64 debian
build-win-arm32

00:00:27

passed #346389
amd64 debian
build-win-arm64

00:00:32

passed #346385
amd64 debian
build-win32

00:00:45

passed #346386
amd64 debian
build-win32-unaligned-stack

00:00:42

passed #346387
amd64 debian
build-win64

00:00:51

 
  Test
failed #346398
amd64 debian
test-debian

00:00:48

failed #346404
debian aarch64
test-debian-aarch64

00:02:00

failed #346406
debian armv7
test-debian-armv7-clang-5

00:02:40

failed #346400
amd64 debian
test-debian-asan

00:02:32

failed #346401
amd64 debian
test-debian-msan

00:01:22

failed #346405
docker ppc64le
test-debian-ppc64le

00:01:25

failed #346402
amd64 debian
test-debian-ubsan

00:01:41

failed #346399
amd64 debian
test-debian-unaligned-stack

00:00:48

failed #346403
amd64 debian
test-win64

00:01:10

 
Name Stage Failure
failed
test-win64 Test
Unexpected Pass:       0
Skipped: 0
Timeout: 0


real 0m14.236s
user 1m26.972s
sys 0m23.988s
ERROR: Job failed: exit code 1
failed
test-debian-ubsan Test
Unexpected Pass:       0
Skipped: 0
Timeout: 0


real 0m39.947s
user 11m48.364s
sys 0m10.788s
ERROR: Job failed: exit code 1
failed
test-debian-armv7-clang-5 Test
Unexpected Pass:       0
Skipped: 0
Timeout: 0


real 1m0.496s
user 4m32.584s
sys 0m47.842s
ERROR: Job failed: exit code 1
failed
test-debian-asan Test
Unexpected Pass:       0
Skipped: 0
Timeout: 0


real 0m33.002s
user 8m35.480s
sys 0m16.136s
ERROR: Job failed: exit code 1
failed
test-debian-msan Test
Unexpected Pass:       0
Skipped: 0
Timeout: 0


real 0m48.379s
user 12m33.908s
sys 0m19.996s
ERROR: Job failed: exit code 1
failed
test-debian-unaligned-stack Test
Unexpected Pass:       0
Skipped: 0
Timeout: 0


real 0m8.682s
user 1m6.172s
sys 0m9.416s
ERROR: Job failed: exit code 1
failed
test-debian Test
Unexpected Pass:       0
Skipped: 0
Timeout: 0


real 0m10.272s
user 1m21.408s
sys 0m10.128s
ERROR: Job failed: exit code 1
failed
test-debian-aarch64 Test
FAIL:       3
SKIP: 0
TIMEOUT: 0


real 0m53.241s
user 3m41.652s
sys 0m24.200s
ERROR: Job failed: exit code 1
failed
test-debian-ppc64le Test
Unexpected Pass:       0
Skipped: 0
Timeout: 0


real 0m27.197s
user 1m24.947s
sys 0m3.759s
ERROR: Job failed: exit code 1