vm_backtrace.c (rb_profile_frame_full_label): add new C API
  rb_profile_frame_full_label() which returns label with
  qualified method name.
  Note that in future version of Ruby label() may return
  same return value of full_label().
* ext/-test-/debug/profile_frames.c,
  test/-ext-/debug/test_profile_frames.rb: fix a test for this change.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43205 b2dd03c8-39d4-4d8f-98ff-823fe69b080e