Assert preconditions for MergedAnnotations.from() factory methods

[sbrannen]

If null values are supplied for the RepeatableContainers or AnnotationFilter arguments to from() factory methods in MergedAnnotations, certain operations will eventually result in a NullPointerException.

This is to be expected; however, the NullPointerException is often swallowed and only logged at INFO level with an exception message similar to the following.

Failed to introspect annotations on org.example.MyClass: NullPointerException

In such cases, the INFO log message is not helpful in diagnosing the problem. Furthermore, since the exception is swallowed, the desired operation (e.g., MergedAnnotations.stream(...)) simply returns no
results, and the user is left wondering what happened.