Provides the ability to drop to frame. Drop to frame
generally means popping a selected stack frame (and all frames above it) from
the execution stack and then stepping back into the frame.
Performs a drop to frame on this element. Implementations must generate
events such that debug clients can update appropriately, such as corresponding
RESUME and SUSPEND events, or a single CHANGE
event when the drop is complete. Implementations should implement drop to frame
in a non-blocking fashion.