Return the node from which this break statement is breaking.
This will be either a Statement (in the case of breaking out of a
loop), a SwitchMember (in the case of a labeled break statement whose
label matches a label on a switch case in an enclosing switch statement),
null if the AST has not yet been resolved or if the target could not
be resolved. Note that if the source code has errors, the target might be
invalid (e.g. trying to break to a switch case).
AstNode get target;
Set the node from which this break statement is breaking to the given
set target(AstNode node);