Merge RubyGems-2.7.5 from upstream.
Please see its details: http://blog.rubygems.org/2018/02/06/2.7.5-released.html
test_gem_util.rb: fix broken test
* test/rubygems/test_gem_util.rb: no guarantee that tmpdir is
always underneath the root directory at all.
test_gem_commands_setup_command.rb: BUNDLER_VERS
* test/rubygems/test_gem_commands_setup_command.rb: run bundled
gem command, instead of installed one.
no need to set bundled bundler unless Gem::USE_BUNDLER_FOR_GEMDEPS
revert r62302 and force to define the version constant
Merge RubyGems 2.7.6 from upstream.
It fixed some security vulnerabilities.
http://blog.rubygems.org/2018/02/15/2.7.6-released.html
fix regexp literal warning.
test/rubygems/test_gem_server.rb: eliminate duplicated character class warning.
[Bug #14481]
Remove unnecessary `[]`s
merge revision(s) 62244,62246,62301,62302,62303,62422,62436,62452: [Backport #14481]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_5@62837 b2dd03c8-39d4-4d8f-98ff-823fe69b080e