ci: remove last uses of deprecated swrast alias for softpipe+llvmpipe

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34217>

.gitlab-ci/build/gitlab-ci.yml

@@ -192,7 +192,7 @@ debian-testing-ubsan:
       -Wno-error=stringop-truncation
     CPP_ARGS: >
       -Wno-error=array-bounds
-    GALLIUM_DRIVERS: "swrast"
+    GALLIUM_DRIVERS: "llvmpipe,softpipe"
     VULKAN_DRIVERS: "swrast"
     EXTRA_OPTION: >
       -D b_sanitize=undefined

.gitlab-ci/windows/mesa_build.ps1

@@ -48,7 +48,7 @@ meson setup `
 -Dllvm=enabled `
 -Dshared-llvm=disabled `
 -Dvulkan-drivers="swrast,amd,microsoft-experimental" `
--Dgallium-drivers="swrast,d3d12,zink" `
+-Dgallium-drivers="llvmpipe,softpipe,d3d12,zink" `
 -Dgallium-va=enabled `
 -Dvideo-codecs="all" `
 -Dgles1=enabled `