Exclude a couple tests failing on JRuby for multiple reasons

* jruby/jruby#8972
  but also at least 2 more incompatibilities.

Author: eregon

test/pathname/test_pathname.rb

@@ -370,10 +370,11 @@ def has_hardlink?
   end
 
   def realpath(path, basedir=nil)
-    Pathname.new(path).realpath(basedir).to_s
+    Pathname.new(path).realpath(*basedir).to_s
   end
 
   def test_realpath
+    omit "not working yet" if RUBY_ENGINE == "jruby"
     return if !has_symlink?
     with_tmpchdir('rubytest-pathname') {|dir|
       assert_raise(Errno::ENOENT) { realpath("#{dir}/not-exist") }
@@ -434,6 +435,7 @@ def realdirpath(path)
   end
 
   def test_realdirpath
+    omit "not working yet" if RUBY_ENGINE == "jruby"
     return if !has_symlink?
     Dir.mktmpdir('rubytest-pathname') {|dir|
       rdir = realpath(dir)