Prior to this commit, `VintageTestDescriptor` used the `Description`'s
method name when it wasn't null. However, there are edge cases where it
can be empty which lead to blank display names which are not allowed by
the Platform. Thus, it is now only used if not blank.

Fixes #2248.

JUnit 5.6 introduced inner class cycle detection in
ReflectionSupport.findNestedClasses() (see #2039). Unfortunately, the
cycle detection introduced a regression for test classes that contain
classes with inner class cycles when those inner classes do not match
the predicate supplied to findNestedClasses() (e.g., "is annotated with
@nested"). Consequently, an exception is thrown for any inner class
cycled detected, even if the cycle would not adversely affect test
discovery or execution.

This commit fixes this regression by avoiding inner class cycle
detection for candidate classes that do match the predicate. For
example, within JUnit Jupiter inner class cycle detection is now only
performed for inner classes annotated with @nested.

Fixes #2249

# Conflicts:
#	documentation/documentation.gradle.kts