Remove needless lines

Because both assert_equal and assert_nil do not pass at the same time.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63639 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/test_pty.rb

@@ -196,7 +196,6 @@ class TestPTY < Test::Unit::TestCase
   rescue RuntimeError
     skip $!
   else
-    assert_equal(pid, st1.pid) if st1
     assert_nil(st1)
     assert_equal(pid, st2.pid)
   end
@@ -215,7 +214,6 @@ class TestPTY < Test::Unit::TestCase
   rescue RuntimeError
     skip $!
   else
-    assert_equal(pid, st1.pid) if st1
     assert_nil(st1)
     assert_equal(pid, st2.pid)
   end