JRuby 9.1.7.0 produces a warning from rubygems, ignore it

Author: JonRowe

lib/rspec/support/spec/shell_out.rb

@@ -59,6 +59,7 @@ def strip_known_warnings(input)
           l =~ %r{bundler/source/rubygems} ||
           # Ignore bundler + rubygems warning.
           l =~ %r{site_ruby/\d\.\d\.\d/rubygems} ||
+          l =~ %r{jruby-\d\.\d\.\d\.\d/lib/ruby/stdlib/rubygems} ||
           # This is required for windows for some reason
           l =~ %r{lib/bundler/rubygems} ||
           # This is a JRuby file that generates warnings on 9.0.3.0