test/ruby: suppress warnings

* test/ruby/test_array.rb: (need_continuation): suppress warnings
  to require continuation.

* test/ruby/test_continuation.rb: ditto.

* test/ruby/test_enum.rb: ditto.

* test/ruby/test_fiber.rb: ditto.

* test/ruby/test_hash.rb: ditto.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48642 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
error.c: simplify message building

* error.c (syserr_initialize): simplify message building and get
  rid of potential invalid byte sequence.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48643 b2dd03c8-39d4-4d8f-98ff-823fe69b080e