Remove "profiler" in Ruby 2.7+ standard-libs test

See https://travis-ci.org/docker-library/ruby/jobs/539398758

> `require 'profiler' failed: cannot load such file -- profiler`

test/tests/ruby-standard-libs/container.rb

@@ -106,9 +106,13 @@ if defined?(RUBY_ENGINE) && RUBY_ENGINE == 'jruby'
 end
 
 require 'rubygems/version'
-if Gem::Version.create(RUBY_VERSION) >= Gem::Version.create('2.5')
+rubyVersion = Gem::Version.create(RUBY_VERSION)
+if rubyVersion >= Gem::Version.create('2.5')
 	stdlib.delete('mathn')
 end
+if rubyVersion >= Gem::Version.create('2.7')
+	stdlib.delete('profiler')
+end
 
 result = 'ok'
 stdlib.each do |lib|