Disable color output to avoid appverif problem

There does not appear to be any simple way to use a custom color
class with CATCH2 so we just disable color as is done for a UWP.

Fixes microsoft#679

Signed-off-by: Dave Thaler <dthaler@microsoft.com>

tests/libs/util/catch_wrapper.hpp

@@ -8,5 +8,6 @@
 #pragma warning(disable : 26495) // Always initialize a member variable
 #pragma warning(disable : 26812) // Prefer 'enum class' over 'enum'
 #pragma warning(disable : 26816) // The pointer points to memory allocated on the stack
+#define CATCH_CONFIG_COLOUR_NONE 1
 #include "catch2\catch.hpp"
-#pragma warning(pop)
+#pragma warning(pop)