test_process.rb: clock_getres may not supported

* test/ruby/test_process.rb (test_clock_getres): ignore if
  clock_getres is no supported, e.g., on old Linux.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44698 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_process.rb

@@ -1777,6 +1777,8 @@ EOS
 
   def test_clock_getres
     r = Process.clock_getres(Process::CLOCK_REALTIME, :nanosecond)
+  rescue Errno::EINVAL
+  else
     assert_kind_of(Integer, r)
     assert_raise(Errno::EINVAL) { Process.clock_getres(:foo) }
   end