Tests: Pass generator platform and toolset into check for Fortran

Check for a Fortran compiler that supports the same target platform
as we are testing.

Tests/CheckFortran.cmake

@@ -18,6 +18,8 @@ file(WRITE \"\${CMAKE_CURRENT_BINARY_DIR}/result.cmake\"
   execute_process(
     WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/CheckFortran
     COMMAND ${CMAKE_COMMAND} . -G ${CMAKE_GENERATOR}
+                               -A "${CMAKE_GENERATOR_PLATFORM}"
+                               -T "${CMAKE_GENERATOR_TOOLSET}"
     OUTPUT_VARIABLE output
     ERROR_VARIABLE output
     RESULT_VARIABLE result