Add dart_core.js (fixes #89)

test/test.sh

 #!/bin/bash
 set -e # bail on error
 
 function fail {
   echo -e "Some tests failed"
   return 1
 }
 
 # Arguments passed to the diff tool. We exclude:
 #  - *.map files so they aren't compared, as the diff is not human readable.
 #  - runtime JS files that are just copied over from the sources and are not
 #    duplicated in the expected folder.
 DIFF_ARGS="-u -r -N --exclude=\*.map \
   --exclude=dart_runtime.js \
+  --exclude=dart_core.js \
   --exclude=harmony_feature_check.js \
   --exclude=messages_widget.js \
   --exclude=messages.css \
   expect actual"
 
 function show_diff {
   echo "Fail: actual output did not match expected"
   echo
   diff $DIFF_ARGS |\
     sed -e "s/^\(+.*\)/\1/" |\
@@ skipping 54 matching lines @@
 #   * local files that have never been added to git,
 #   * subdirectories of test/ and tool/, unless explicitly added. Those dirs
 #     contain a lot of generated or external source we should not reformat.
 (files=`git ls-files 'bin/*.dart' 'lib/*.dart' test/*.dart test/checker/*.dart \
   tool/*.dart | grep -v lib/src/js/`; git status -s $files | grep -q . \
   && echo "Did not run the formatter, please commit edited files first." \
   || (echo "Running dart formatter" ; pub run dart_style:format -w $files))
 popd &> /dev/null
 
 echo -e "All tests pass"