[ruby-cvs:79088] beb59c3b45 (master): Add GC guard

Kazuhiro NISHIYAMA	2020-01-08 12:26:48 +0900 (Wed, 08 Jan 2020)

  New Revision: beb59c3b45

  https://github.com/ruby/ruby/commit/beb59c3b45

  Log:
    Add GC guard
    =

    Try to fix infrequent error:
    =

    https://rubyci.org/logs/rubyci.s3.amazonaws.com/solaris10-sunc/ruby-m=
aster/log/20200108T010004Z.fail.html.gz
    ```
      1) Error:
    DRbTests::TestDRbSSLCore#test_02_basic_object:
    RangeError: "348" is recycled object
        (drbssl://localhost:58371) /export/home/users/chkbuild/cb-sunc/tm=
p/build/20200108T010004Z/ruby/lib/drb/drb.rb:366:in `_id2ref'
        (drbssl://localhost:58371) /export/home/users/chkbuild/cb-sunc/tm=
p/build/20200108T010004Z/ruby/lib/drb/drb.rb:366:in `to_obj'
        (drbssl://localhost:58371) /export/home/users/chkbuild/cb-sunc/tm=
p/build/20200108T010004Z/ruby/lib/drb/drb.rb:1537:in `to_obj'
        (drbssl://localhost:58371) /export/home/users/chkbuild/cb-sunc/tm=
p/build/20200108T010004Z/ruby/lib/drb/drb.rb:1856:in `to_obj'
        (drbssl://localhost:58371) /export/home/users/chkbuild/cb-sunc/tm=
p/build/20200108T010004Z/ruby/lib/drb/drb.rb:620:in `recv_request'
        (drbssl://localhost:58371) /export/home/users/chkbuild/cb-sunc/tm=
p/build/20200108T010004Z/ruby/lib/drb/drb.rb:931:in `recv_request'
        (drbssl://localhost:58371) /export/home/users/chkbuild/cb-sunc/tm=
p/build/20200108T010004Z/ruby/lib/drb/drb.rb:1665:in `init_with_client'
        (drbssl://localhost:58371) /export/home/users/chkbuild/cb-sunc/tm=
p/build/20200108T010004Z/ruby/lib/drb/drb.rb:1677:in `setup_message'
        (drbssl://localhost:58371) /export/home/users/chkbuild/cb-sunc/tm=
p/build/20200108T010004Z/ruby/lib/drb/drb.rb:1641:in `perform'
        (drbssl://localhost:58371) /export/home/users/chkbuild/cb-sunc/tm=
p/build/20200108T010004Z/ruby/lib/drb/drb.rb:1734:in `block (2 levels) in=
 main_loop'
        (drbssl://localhost:58371) /export/home/users/chkbuild/cb-sunc/tm=
p/build/20200108T010004Z/ruby/lib/drb/drb.rb:1730:in `loop'
        (drbssl://localhost:58371) /export/home/users/chkbuild/cb-sunc/tm=
p/build/20200108T010004Z/ruby/lib/drb/drb.rb:1730:in `block in main_loop'=

        /export/home/users/chkbuild/cb-sunc/tmp/build/20200108T010004Z/ru=
by/test/drb/drbtest.rb:163:in `test_02_basic_object'
    ```

  Modified files:
    test/drb/ut_drb.rb=