Skip test with return code 77

Skipping a test with Meson or CMake by returning error code 77 is a de facto practice. Sometimes it is only feasible to know a test should be skipped by attempting to run that test.

Meson build system accepts return code 77 by default as a signal to skip the test. Configure CMake to skip return code:

add_test(NAME MyTest COMMAND mytest)  # arbitrary
set_tests_properties(MyTest PROPERTIES SKIP_RETURN_CODE 77)