#279 Incorrect ClassLoader used to instantiate test class when using RunWith annotation.

Defer initialization of the class under test until the custom runner specified with @RunWith is initialized.  This will allow the Runner to manipulate the class under test if so desired.
ex. Robolectric uses a custom ClassLoaders to provide “shadow” object of Android system classes for testing purposes.
Merge branch 'junit_test_class_loading' of https://github.com/curtpm/gradle
GRADLE-3114 - don't eagerly load JUnit test classes.