anv: Implement VK_EXT_descriptor_indexing

Now that everything is in place to do bindless for all resource types
except input attachments and UBOs, VK_EXT_descriptor_indexing is
"trivial".
25 jobs for !103 with review/anv-a64-ssbo in 23 minutes and 15 seconds (queued for 2 seconds)
detached
Status Job ID Name Coverage
  Containers Build
passed #148338
containers:ubuntu

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  Build+Test
passed #148353
build:make-gallium-drivers-other

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passed #148352
build:make-gallium-drivers-radeonsi

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passed #148351
build:make-gallium-drivers-swr

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passed #148354
build:make-gallium-st-clover-llvm-39

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passed #148355
build:make-gallium-st-clover-llvm-4

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passed #148356
build:make-gallium-st-clover-llvm-5

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passed #148357
build:make-gallium-st-clover-llvm-6

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passed #148358
build:make-gallium-st-clover-llvm-7

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passed #148359
build:make-gallium-st-other

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passed #148350
build:make-loader-classic-dri

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passed #148349
build:make-vulkan

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passed #148345
build:meson-gallium-clover-llvm5

00:02:02

passed #148346
build:meson-gallium-clover-llvm6

00:03:51

passed #148347
build:meson-gallium-clover-llvm7

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passed #148344
build:meson-gallium-drivers-other

00:08:21

passed #148343
build:meson-gallium-radeonsi

00:03:24

passed #148348
build:meson-gallium-st-other

00:03:22

passed #148342
build:meson-gallium-swr

00:11:09

passed #148341
build:meson-glvnd

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passed #148340
build:meson-loader-classic-dri

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passed #148339
build:meson-vulkan

00:03:09

passed #148361
build:scons-llvm

00:03:32

passed #148360
build:scons-nollvm

00:03:54

passed #148362
build:scons-swr

00:07:51