[Tests] review of test_config files

Makefile

src/plugins/dive/tests/test_config

src/plugins/loop_analysis/tests/test_config

src/plugins/nonterm/tests/test_config

src/plugins/variadic/tests/test_config

tests/cil/test_config

tests/libc/test_config

tests/pretty_printing/test_config

tests/slicing/test_config

tests/spec/test_config

tests/syntax/test_config

tests/test_config