Fix tests which fail with extra stderr output when a Thread dies

* [Feature #14143] [ruby-core:83979].

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61186 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/digest/test_digest.rb

@@ -264,6 +264,7 @@ module TestDigest
         assert_nothing_raised {
           t = Thread.start {
             sleep 0.1
+            Thread.current.report_on_exception = false
             Digest::Foo.new
           }
           Digest(:Foo).new

test/ruby/test_io.rb

@@ -2911,11 +2911,15 @@ __END__
         $stdin.reopen(r)
         r.close
         read_thread = Thread.new do
+          begin
             $stdin.read(1)
+          rescue IOError => e
+            e
+          end
         end
         sleep(0.1) until read_thread.stop?
         $stdin.close
-        assert_raise(IOError) {read_thread.join}
+        assert_kind_of(IOError, read_thread.value)
       end
     end;
   end
@@ -3539,8 +3543,10 @@ __END__
         thread = Thread.new do
           begin
             q << true
+            assert_raise_with_message(IOError, /stream closed/) do
               while r.gets
               end
+            end
           ensure
             closed = r.closed?
           end
@@ -3548,9 +3554,7 @@ __END__
         q.pop
         sleep 0.01 until thread.stop?
         r.close
-        assert_raise_with_message(IOError, /stream closed/) do
         thread.join
-        end
         assert_equal(true, closed, bug13158 + ': stream should be closed')
       end
     end;