assertions.rb: add an alias pend for skip

* test/lib/test/unit/assertions.rb (pend): Add an alias 'pend' for
  'skip'. This is required for test-unit compatibility. In particular,
  ext/openssl uses it.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56025 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/lib/test/unit/assertions.rb

@@ -452,6 +452,9 @@ EOT
         assert(failed.empty?, message(m) {failed.pretty_inspect})
       end
 
+      # compatiblity with test-unit
+      alias pend skip
+
       def assert_valid_syntax(code, fname = caller_locations(1, 1)[0], mesg = fname.to_s, verbose: nil)
         code = code.b
         code.sub!(/\A(?:\xef\xbb\xbf)?(\s*\#.*$)*(\n)?/n) {