LANG-1647 - Check if an throwable is a checked exception

[arturobernalg]

The idea it's have a function that check if a given throwable is a checked exception. There are some similar function in ConcurrentUtils, but have package visibility and return the same exception. Seem logic have this verification in the class that have this responsibility - ExceptionUtils

[coveralls]

Coverage increased (+0.007%) to 94.936% when pulling 73f2b7381dc0e68e1fb8ba311434b6af1ebdd7b3 on arturobernalg:feature/LANG-1647 into 6b9964ff4b89205d63eac3db005757edf19e9dda on apache:master.