gallium/u_threaded: don't set is_user_buffer = false in set_vertex_buffers

It's not necessary. An assertion should be enough.
88 jobs for !8184 with opt-upload-threaded in 11 seconds (queued for 4 seconds)
detached
Status Job ID Name Coverage
  Sanity
passed #6289586
sanity

00:00:11

 
  Container
manual #6289589
aarch64 manual
arm_build
manual #6289590
manual
arm_test-base
manual #6289591
windows shell 1809 mesa manual
windows_build_vs2019
manual #6289587
manual
x86_build-base
manual #6289588
manual
x86_test-base
 
  Container 2
created #6289599
android_build
created #6289602
arm64_test
created #6289603
armhf_test
created #6289596
i386_build
created #6289592
kernel+rootfs_amd64
created #6289593
aarch64
kernel+rootfs_arm64
created #6289594
aarch64
kernel+rootfs_armhf
created #6289597
ppc64el_build
created #6289598
s390x_build
created #6289595
x86_build
created #6289600
x86_test-gl
created #6289601
x86_test-vk
 
  Meson X86 64
created #6289609
meson-clang
created #6289610
meson-clover
created #6289606
meson-clover-testing
created #6289607
meson-gallium
created #6289608
meson-release
created #6289604
meson-testing
created #6289605
meson-testing-asan
created #6289611
meson-vulkan
 
  Build Misc
created #6289612
meson-android
created #6289614
aarch64
meson-arm64
created #6289615
aarch64
meson-arm64-build-test
created #6289613
aarch64
meson-armhf
created #6289618
meson-i386
created #6289621
meson-mingw32-x86_64
created #6289620
kvm
meson-ppc64el
created #6289619
kvm
meson-s390x
created #6289616
docker windows 1809 mesa
meson-windows-vs2019
created #6289617
allowed to fail
scons-win64
 
  Amd
created #6289622
mesa-ci-aarch64-lava-collabora
radeonsi-stoney-gles2:amd64
created #6289624
mesa-ci-aarch64-lava-collabora
radeonsi-stoney-gles31:amd64
created #6289623
mesa-ci-aarch64-lava-collabora
radeonsi-stoney-gles3:amd64
created #6289625
mesa-ci-aarch64-lava-collabora
radeonsi-stoney-traces:amd64
created #6289626
radv-fossils
 
  Arm
created #6289632
mesa-ci-aarch64-lava-collabora
panfrost-g52-gles2:arm64
created #6289627
mesa-ci-aarch64-lava-collabora
panfrost-t720-gles2:arm64
created #6289628
mesa-ci-aarch64-lava-collabora
panfrost-t860-gles2:arm64
created #6289629
mesa-ci-aarch64-lava-collabora
panfrost-t860-gles3:arm64 1/2
created #6289630
mesa-ci-aarch64-lava-collabora
panfrost-t860-gles3:arm64 2/2
created #6289631
mesa-ci-aarch64-lava-collabora
panfrost-t860-traces:arm64
 
  Freedreno
created #6289642
google-freedreno-db410c
arm64_a306_gles2
created #6289643
google-freedreno-db410c
arm64_a306_gles3
created #6289644
google-freedreno-db410c
arm64_a306_gles3_options
created #6289645
google-freedreno-db820c
arm64_a530_gles2 1/2
created #6289646
google-freedreno-db820c
arm64_a530_gles2 2/2
created #6289647
google-freedreno-db820c
arm64_a530_gles3
created #6289648
google-freedreno-db820c
arm64_a530_gles31
created #6289637
google-freedreno-cheza
arm64_a630_gl
created #6289633
google-freedreno-cheza
arm64_a630_gles2
created #6289635
google-freedreno-cheza
arm64_a630_gles3
created #6289634
google-freedreno-cheza
arm64_a630_gles31
created #6289638
google-freedreno-cheza
arm64_a630_gles_others
created #6289636
google-freedreno-cheza
arm64_a630_traces
created #6289639
google-freedreno-cheza
arm64_a630_vk 1/2
created #6289640
google-freedreno-cheza
arm64_a630_vk 2/2
created #6289641
google-freedreno-cheza
arm64_a630_vk_sysmem
 
  Raspberrypi
created #6289649
igalia-rpi3
vc4-rpi3-gles2:armhf 1/4
created #6289650
igalia-rpi3
vc4-rpi3-gles2:armhf 2/4
created #6289651
igalia-rpi3
vc4-rpi3-gles2:armhf 3/4
created #6289652
igalia-rpi3
vc4-rpi3-gles2:armhf 4/4
 
  Software Renderer
created #6289663
lavapipe-vk
created #6289657
llvmpipe-gles2
created #6289653
llvmpipe-piglit-cl
created #6289655
llvmpipe-piglit-glslparser
created #6289654
llvmpipe-piglit-quick_gl
created #6289656
llvmpipe-piglit-quick_shader
created #6289664
llvmpipe-traces
created #6289662
softpipe-gl
created #6289658
softpipe-gles2
created #6289659
softpipe-gles3
created #6289660
softpipe-gles31 1/2
created #6289661
softpipe-gles31 2/2
 
  Layered Backends
created #6289665
docker windows 1809 mesa
test-d3d12-windows
created #6289670
virgl-gl30-on-gl
created #6289671
virgl-gl31-on-gl
created #6289672
virgl-gl32-on-gl
created #6289666
virgl-gles2-on-gl
created #6289668
virgl-gles31-on-gl 1/2
created #6289669
virgl-gles31-on-gl 2/2
created #6289667
virgl-gles3-on-gl
created #6289673
virgl-traces