Enable Vulkan viz_unittests on MSAN builds

The failure is fixed by:
https://swiftshader-review.googlesource.com/c/SwiftShader/+/32128

Bug: 960795,967824
Change-Id: I5ca2815aeee32051f187e6a7303e99bf101498ae
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1635810
Commit-Queue: Jonathan Ross <jonross@chromium.org>
Auto-Submit: Saman Sami <samans@chromium.org>
Reviewed-by: Jonathan Ross <jonross@chromium.org>
Cr-Commit-Position: refs/heads/master@{#664736}

components/viz/service/BUILD.gn

@@ -488,10 +488,9 @@ viz_source_set("unit_tests") {
   }
 
   # TODO(samans): Support more configurations.
-  # MSAN issue: https://crbug.com/967819
   # CFI issue: https://crbug.com/967819
   # x86 issue: https://crbug.com/967831
-  if (use_x11 && !is_msan && target_cpu != "x86" && !is_cfi) {
+  if (use_x11 && target_cpu != "x86" && !is_cfi) {
     defines = [ "ENABLE_VIZ_VULKAN_TESTS" ]
   }
 }