require_relative fails for relative paths within jars on Windows #3197
Description
We use gems in a jar to simplify distribution of the gems used for test runs.
When requiring rspec, rspec internally uses require_relative, which then fails. I notice there is a weird mix of the two different slash directions, which probably explains why I'm not seeing the same problem on OSX:
Errno::ENOENT: No such file or directory - C:\hudson\workspace\trunk-functional-tests\os\windows\dependencies\jruby\jruby-testing-gems.jar!\gems\rspec-support-3.3.0\lib\rspec\support.rb
realpath at org/jruby/RubyFile.java:805
require_relative at uri:classloader:/jruby/kernel/kernel.rb:21
block in Support at c:/hudson/workspace/trunk-functional-tests/os/windows/dependencies/jruby/jruby-testing-gems.jar!/gems/rspec-support-3.3.0/lib/rspec/support.rb:28
call at org/jruby/RubyProc.java:308
block in require_rspec_support at c:/hudson/workspace/trunk-functional-tests/os/windows/dependencies/jruby/jruby-testing-gems.jar!/gems/rspec-support-3.3.0/lib/rspec/support.rb:19
<module:Support> at c:/hudson/workspace/trunk-functional-tests/os/windows/dependencies/jruby/jruby-testing-gems.jar!/gems/rspec-support-3.3.0/lib/rspec/support.rb:29
<module:RSpec> at c:/hudson/workspace/trunk-functional-tests/os/windows/dependencies/jruby/jruby-testing-gems.jar!/gems/rspec-support-3.3.0/lib/rspec/support.rb:2
<top> at c:/hudson/workspace/trunk-functional-tests/os/windows/dependencies/jruby/jruby-testing-gems.jar!/gems/rspec-support-3.3.0/lib/rspec/support.rb:1
require at org/jruby/RubyKernel.java:940
(root) at uri:classloader:/META-INF/jruby.home/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:1
<top> at uri:classloader:/META-INF/jruby.home/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:54
require at org/jruby/RubyKernel.java:940
(root) at c:/hudson/workspace/trunk-functional-tests/os/windows/dependencies/jruby/jruby-testing-gems.jar!/gems/rspec-core-3.3.2/lib/rspec/core.rb:5
<top> at uri:classloader:/META-INF/jruby.home/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:1
require at org/jruby/RubyKernel.java:940
require at uri:classloader:/META-INF/jruby.home/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:54
<top> at c:\hudson\workspace\trunk-functional-tests\os\windows/functional-tests/run-rspec.rb:8