microsoft/compiler: Fix clang fallthrough warnings

Reviewed-by: Adam Jackson <ajax@redhat.com>
Part-of: <!8248>
38 jobs for !8248 with d3d12-gcc-werror in 10 minutes and 38 seconds (queued for 2 seconds)
detached
Status Job ID Name Coverage
  Sanity
passed sanity #6426225

00:00:09

 
  Container
passed arm_build #6426231
aarch64

00:00:20

passed arm_test-base #6426234

00:00:14

passed windows_build_vs2019 #6426236
windows shell 1809 mesa

00:00:22

passed x86_build-base #6426227

00:00:12

passed x86_test-base #6426229

00:00:13

 
  Container 2
passed android_build #6426251

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passed arm64_test #6426257

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passed armhf_test #6426259

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passed i386_build #6426247

00:00:16

passed kernel+rootfs_amd64 #6426239

00:00:12

passed kernel+rootfs_arm64 #6426241
aarch64

00:00:20

passed kernel+rootfs_armhf #6426243
aarch64

00:00:20

passed ppc64el_build #6426248

00:00:12

passed s390x_build #6426250

00:00:16

passed x86_build #6426245

00:00:15

passed x86_test-gl #6426253

00:00:15

passed x86_test-vk #6426255

00:00:14

 
  Meson X86 64
passed meson-clang #6426270

00:02:53

passed meson-clover #6426271

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passed meson-clover-testing #6426265

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passed meson-gallium #6426266

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passed meson-release #6426268

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passed meson-testing #6426345

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passed meson-testing-asan #6426263

00:03:08

passed meson-vulkan #6426273

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failed meson-testing #6426261

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  Build Misc
passed meson-android #6426275

00:00:37

passed meson-arm64 #6426279
aarch64

00:01:28

passed meson-arm64-build-test #6426281
aarch64

00:01:25

passed meson-armhf #6426277
aarch64

00:01:28

passed meson-i386 #6426287

00:02:20

passed meson-mingw32-x86_64 #6426293

00:02:23

passed meson-ppc64el #6426291
kvm

00:02:47

passed meson-s390x #6426289
kvm

00:03:15

passed meson-windows-vs2019 #6426283
windows docker 1809 mesa

00:03:58

passed scons-win64 #6426285

00:03:54

 
  Layered Backends
passed test-d3d12-windows #6426294
windows docker 1809 mesa

00:03:44