merges r21084 from trunk into ruby_1_9_1.

* vm_insnhelper.c (vm_call_method, vm_call_cfunc): use original id instead of
  calling id when NODE_CFUNC or NODE_BMETHOD.
  fixes Bug #632 [ruby-core:19282].
* vm_eval.c (vm_call0, vm_call_super): ditto.
* vm_method.c (rb_add_method, rb_alias): store original id
  in nd_file field of NODE_METHOD.
* test/stringio/test_stringio.rb: add a test.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@21113 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/stringio/test_stringio.rb

@@ -379,4 +379,19 @@ class TestStringIO < Test::Unit::TestCase
     assert_equal(4, f.size)
   end
 
+  # This test is should in ruby/test_method.rb
+  # However this test depends on stringio library,
+  # we write it here.
+  class C < StringIO
+    alias old_init initialize
+    attr_reader :foo
+    def initialize
+      @foo = :ok
+      old_init
+    end
+  end
+
+  def test_method
+    assert_equal(:ok, C.new.foo, 'Bug #632 [ruby-core:19282]')
+  end
 end