Ruby

test/dtrace: use TracePoint.__enable

"TracePoint.enable" is implemented in prelude.rb since
r66003 / commit 96990203b71184003cf8a9bad5cc177645820fd4
and not available in miniruby. I tried using regular "ruby"
for testing, but it proved noisy and caused test failures.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66336 b2dd03c8-39d4-4d8f-98ff-823fe69b080e