mesa: Handle pbuffers in desktop GL framebuffer attachment queries

Once again, we were handling back-to-front in the GLES3 case, but not
the desktop GL case.

Fixes GTF-GL46.gtf30.GL3Tests.framebuffer_srgb.framebuffer_srgb_default_encoding when run with --deqp-surface-type=pbuffer --deqp-gl-context-type=egl.

Reviewed-by: Kristian H. Kristensen <hoegsberg@google.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
48 jobs for !2330 with back2front in 23 minutes and 25 seconds (queued for 4 seconds)
detached
Status Job ID Name Coverage
  Container
passed #752423
debian-10

00:00:22

passed #752424
debian-9

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passed #752422
lava-container:arm64

00:00:21

passed #752421
lava-container:armhf

00:00:21

passed #752425
aarch64
test-container:arm64

00:00:19

 
  Build
passed #752427
lava-build:arm64

00:05:03

passed #752426
lava-build:armhf

00:05:01

passed #752430
meson-arm64

00:06:25

passed #752429
meson-armhf

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passed #752432
meson-clang

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passed #752435
meson-clover

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passed #752436
meson-clover-old-llvm

00:06:17

passed #752438
meson-i386

00:05:12

passed #752428
meson-main

00:11:07

passed #752431
meson-swr-glvnd

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passed #752437
meson-vulkan

00:03:25

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scons

00:19:18

passed #752440
scons-old-llvm

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passed #752433
scons-swr

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passed #752434
scons-win64

00:06:43

 
  Test
passed #752465
db410c
arm64_a306_gles2 1/4

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passed #752466
db410c
arm64_a306_gles2 2/4

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passed #752467
db410c
arm64_a306_gles2 3/4

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passed #752468
db410c
arm64_a306_gles2 4/4

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passed #752454
mesa-cheza
arm64_a630_gles2

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passed #752455
mesa-cheza
arm64_a630_gles31 1/4

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passed #752456
mesa-cheza
arm64_a630_gles31 2/4

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passed #752457
mesa-cheza
arm64_a630_gles31 3/4

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passed #752458
mesa-cheza
arm64_a630_gles31 4/4

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passed #752459
mesa-cheza
arm64_a630_gles3 1/6

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passed #752460
mesa-cheza
arm64_a630_gles3 2/6

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mesa-cheza
arm64_a630_gles3 3/6

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mesa-cheza
arm64_a630_gles3 4/6

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passed #752463
mesa-cheza
arm64_a630_gles3 5/6

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passed #752464
mesa-cheza
arm64_a630_gles3 6/6

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passed #752444
lava-meson-gxl-s905x-libretech-cc
lima-test:arm64

00:08:32

passed #752443
lava-sun8i-h3-libretech-all-h3-cc
lima-test:armhf

00:17:57

passed #752441
lava-rk3288-veyron-jaq
panfrost-t760-test:armhf

00:09:04

passed #752442
lava-rk3399-gru-kevin
panfrost-t860-test:arm64

00:07:59

passed #752445
test-llvmpipe-gles2 1/4

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passed #752446
test-llvmpipe-gles2 2/4

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passed #752447
test-llvmpipe-gles2 3/4

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passed #752448
test-llvmpipe-gles2 4/4

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passed #752449
test-softpipe-gles2 1/4

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passed #752450
test-softpipe-gles2 2/4

00:01:36

passed #752451
test-softpipe-gles2 3/4

00:01:42

passed #752452
test-softpipe-gles2 4/4

00:01:31

passed #752453
test-softpipe-gles3-limited

00:04:05