ci: Enable more VS tests that use managed code

A couple of VS tests were conditioned on `NOT CMAKE_GENERATOR_TOOLSET`,
but in CI jobs with VS we always set `CMAKE_GENERATOR_TOOLSET`.  Make
the condition specific to excluding the `v90` toolset, which was its
original intention anyway.

Tests/CMakeLists.txt

@@ -2234,7 +2234,7 @@ if(BUILD_TESTING)
     endif()
 
     if(NOT "${CMAKE_GENERATOR}" MATCHES "Visual Studio 9 "
-        AND NOT CMAKE_GENERATOR_TOOLSET)
+        AND NOT CMAKE_GENERATOR_TOOLSET STREQUAL "v90")
       ADD_TEST_MACRO(VSWindowsFormsResx VSWindowsFormsResx)
       ADD_TEST_MACRO(VSManagedCustomCommand)
     endif()