Split ArtJvmtiEvent::kClassFileLoadHook in two.

Since the ClassFileLoadHook event is sent to different environments
based on when it is invoked we split the event in two behind the
scenes. The event dispatcher is responsible for making sure that
either or both of the appropriate underlying events are invoked when a
JVMTI_EVENT_CLASS_FILE_LOAD_HOOK is sent.

We also make sure to modify the EventHandler so it sends the correct
events in the correct places when an environment changes its
capabilities.

Bug: 32369913
Bug: 31684920

Test: mma -j40 test-art-host

Change-Id: I82567fc66debe0b658e8d7fced6284a8c4355b7a