envutil.rb: improve assert_no_memory_leak

* test/ruby/envutil.rb (assert_no_memory_leak): allow envirionment
  variables keyword options.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43337 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
envutil.rb: use **opt

* test/ruby/envutil.rb: use **opt to call invoke_ruby.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43338 b2dd03c8-39d4-4d8f-98ff-823fe69b080e