[Backport #7624]

* vm_trace.c (rb_threadptr_exec_event_hooks): added a parameter to pop
  a frame before JUMP_TAG() if exception occurred. This change fix bug
  of Ruby 1.9. [ruby-core:51128] [ruby-trunk - Bug #7624]

* vm_core.h (EXEC_EVENT_HOOK_AND_POP_FRAME): add to use
  `rb_threadptr_exec_event_hooks()' with the pop flag.

* vm.c (vm_exec): use EXEC_EVENT_HOOK_AND_POP_FRAME() while exception
  handling. While exception hadnling, if an exception is raised in
  hooks, need to pop current frame and raise this raised exception by
  hook.

* bootstraptest/test_flow.rb: add a test.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_3@38778 b2dd03c8-39d4-4d8f-98ff-823fe69b080e