Redmine

Running test via `rake test:system test` errs with TypeError because some test class names are overlapping.

$ bundle e rake test:system test
Mercurial test repository NOT FOUND. Skipping functional tests !!!
rake aborted!
TypeError: superclass mismatch for class IssuesTest
.../redmine/test/integration/issues_test.rb:22:in `<top (required)>'
.../activesupport-5.2.3/lib/active_support/dependencies.rb:291:in `require'
.../activesupport-5.2.3/lib/active_support/dependencies.rb:291:in `block in require'
.../activesupport-5.2.3/lib/active_support/dependencies.rb:257:in `load_dependency'
.../activesupport-5.2.3/lib/active_support/dependencies.rb:291:in `require'
.../railties-5.2.3/lib/rails/test_unit/runner.rb:50:in `block in load_tests'
.../railties-5.2.3/lib/rails/test_unit/runner.rb:50:in `each'
.../railties-5.2.3/lib/rails/test_unit/runner.rb:50:in `load_tests'
.../railties-5.2.3/lib/rails/test_unit/runner.rb:39:in `run'
.../railties-5.2.3/lib/rails/test_unit/runner.rb:35:in `rake_run'
.../railties-5.2.3/lib/rails/test_unit/testing.rake:16:in `block in <top (required)>'
.../redmine/bin/bundle:4:in `load'
.../redmine/bin/bundle:4:in `<main>'
Tasks: TOP => test
(See full trace by running task with --trace)

The attached patch fixes this error with a minimal patch that appends "System" only to the class names that overlap with integration tests.