gitlab-ci: Enable UBSan for the meson-vulkan job

It doesn't report any errors now.

Reviewed-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index d534345..f8c16dc 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -338,6 +338,10 @@
       -D gallium-xa=false
       -D gallium-nine=false
       -D gallium-opencl=disabled
+      -D b_sanitize=undefined
+      -D c_args=-fno-sanitize-recover=all
+      -D cpp_args=-fno-sanitize-recover=all
+    UBSAN_OPTIONS: "print_stacktrace=1"
     VULKAN_DRIVERS: intel,amd,freedreno
     LLVM_VERSION: "8"
     EXTRA_OPTION: >