Make sure filepaths are expanded on JRuby

Fixes the build on JRuby

features/cucumber_basic.feature

@@ -19,7 +19,7 @@ Feature:
     And I should see the source files:
       | name                                    | coverage |
       | lib/faked_project.rb                    | 100.0 %  |
-      | lib/faked_project/some_class.rb         | 80.0 %  |
+      | lib/faked_project/some_class.rb         | 80.0 %   |
       | lib/faked_project/framework_specific.rb | 75.0 %   |
       | lib/faked_project/meta_magic.rb         | 100.0 %  |
       | features/step_definitions/my_steps.rb   | 100.0 %  |

lib/simplecov/result.rb

@@ -19,10 +19,18 @@ class Result
     # Initialize a new SimpleCov::Result from given Coverage.result (a Hash of filenames each containing an array of
     # coverage data)
     def initialize(original_result)
-      @original_result = original_result.freeze
-      @files = SimpleCov::FileList.new(original_result.map do |filename, coverage|
+      @original_result = original_result.dup
+
+      # Squeeze filepaths (i.e. "/a/b/../c" becomes "/a/c")
+      @original_result.keys.each do |filename|
+        expanded_filename = File.expand_path filename
+        @original_result[expanded_filename] = @original_result.delete filename
+      end
+
+      @files = SimpleCov::FileList.new(@original_result.map do |filename, coverage|
         SimpleCov::SourceFile.new(filename, coverage) if File.file?(filename)
       end.compact.sort_by(&:filename))
+
       filter!
     end