* include/ruby/ruby.h, gc.c: add new internal event
  RUBY_INTERNAL_EVENT_GC_END. This event invokes at the end of
  after_sweep().
  Time chart with lazy sweep is here:
  (1) Kick RUBY_INTERNAL_EVENT_GC_START
  (2) [gc_marks()]
  (3) [lazy_sweep()]
  (4) [... run Ruby program (mutator) with lazy_sweep() ...]
  (5) [after_sweep()]
  (6) Kick RUBY_INTERNAL_EVENT_GC_END
  (7) [... run Ruby program (mutator), and go to (1) ...]
* ext/-test-/tracepoint/tracepoint.c,
  test/-ext-/tracepoint/test_tracepoint.rb: modify a test.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40963 b2dd03c8-39d4-4d8f-98ff-823fe69b080e