jruby-rack adjust_gem_path has no effect #3828
Description
Environment
when investigating the broken j2ee tests on travis it shows that the ENV['GEM_PATH'] set by jruby-rack has no effect on Gem.path and so does not show up in the testcase.
Expected Behavior
jruby does not call Gem.path before requiring a file outside the core.
Actual Behavior
[INFO] uri:classloader:/META-INF/jruby.home/lib/ruby/stdlib/rubygems.rb:403:in `path'
[INFO] uri:classloader:/META-INF/jruby.home/lib/ruby/stdlib/rubygems/dependency.rb:316:in `to_specs'
[INFO] uri:classloader:/META-INF/jruby.home/lib/ruby/stdlib/rubygems/dependency.rb:330:in `to_spec'
[INFO] uri:classloader:/META-INF/jruby.home/lib/ruby/stdlib/rubygems/core_ext/kernel_gem.rb:65:in `gem'
[INFO] uri:classloader:/jruby/kernel/gem_prelude.rb:9:in `<top>'
[INFO] file:/Users/cmeier/.m2/repository/org/jruby/jruby-core/9.1.0.0-SNAPSHOT/jruby-core-9.1.0.0-SNAPSHOT.jar!/jruby/preludes.rb:1:in `load'
[INFO] file:/Users/cmeier/.m2/repository/org/jruby/jruby-core/9.1.0.0-SNAPSHOT/jruby-core-9.1.0.0-SNAPSHOT.jar!/jruby/preludes.rb:1:in `<top>'
which gets activated on jruby startup.
commit 4a8a2bc introduce this problem.