add unit tests for #[dynamic_link] and #[callable_point]
Due to the limitations of proc macro test implementation,
test logic cannot be added where attribute and proc-macro-error are used.
Types of changes
[ ] Bug fix (changes which fixes an issue)
[ ] New feature (changes which adds functionality)
[ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
Description
Closes #186
Types of changes
Checklist