gtest: backport ansi color fix

Fixes ubsan runs for Mesa3D.

Adds prevents from returning
nullptr by choosing default color.

Upstream PR: https://github.com/google/googletest/pull/4322

Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/9404
Signed-off-by: David Heidelberg <david.heidelberg@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24783>

src/gtest/src/gtest.cc

@@ -3216,7 +3216,8 @@ static const char* GetAnsiColorCode(GTestColor color) {
     case GTestColor::kYellow:
       return "3";
     default:
-      return nullptr;
+      assert(false);
+      return "9" ;
   }
 }