Previously, we only caught subclasses of Exception, however, there are
some cases when Errors are thrown instead of Exceptions. These two cases
are `assert` and when a class cannot be found.
Without this change, the exception would bubble up to the
`uncaughtExceptionHandler`, which would in turn, exit the JVM
(related: #19923).
A note of difference between regular Java asserts and Groovy asserts,
from http://docs.groovy-lang.org/docs/latest/html/documentation/core-testing-guide.html
"Another important difference from Java is that in Groovy assertions are
enabled by default. It has been a language design decision to remove the
possibility to deactivate assertions."
In the event that a user uses an assert such as:
```groovy
def bar=false; assert bar, "message";
```
The GroovyScriptEngineService throws a NoClassDefFoundError being unable
to find the `java.lang.StringBuffer` class. It is *highly* recommended
that any Groovy scripting user switch to using regular exceptions rather
than unconfiguration Groovy assertions.
Resolves#19806
aab8c1f032