Usually we use the name 'block' for a RubyProc, not an arbitrary unit of code.
Fixes #1270 on master.
Conflicts: core/src/main/java/org/jruby/RubyProc.java core/src/main/java/org/jruby/javasupport/JavaMethod.java core/src/main/java/org/jruby/javasupport/JavaSupport.java This commit puts JavaSupport back the way it was, so we can git mv instead and get merging across that move.
The old logic here was turning all breaks that pass through an escaped proc into LongJumpError, even if they originated in a different frame/proc that could still validly handle the break. This commit modifies the logic to ignore the exception altogether (re-throwing it) if it is not associated with this proc/frame (by checking jumpTarget). Fixes #1270