vm_dump.c: no methods in segv handler

* vm_dump.c (rb_vm_bugreport): get rid of calling methods in sigsegv
  handler.  based on a patch by charliesome (Charlie Somerville)
  [ruby-core:49573] [Bug #7402]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38041 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_rubyoptions.rb

@@ -508,6 +508,13 @@ class TestRubyOptions < Test::Unit::TestCase
       )x,
       nil,
       opts)
+
+    bug7402 = '[ruby-core:49573]'
+    status = assert_in_out_err(['-e', 'class Bogus; def to_str; exit true; end; end',
+                                '-e', '$".unshift Bogus.new',
+                                '-e', 'Process.kill :SEGV, $$'],
+                               "", //, /#<Bogus:/)
+    assert_not_predicate(status, :success?, "segv but success #{bug7402}")
   end
 
   def test_DATA