We need to support the "arguments" object. At least the following tests depend on it and are failing: ecma/ExecutionContexts/10.1.6.js ecma/ExecutionContexts/10.1.8-1.js ecma/ExecutionContexts/10.1.8-2.js ecma/Expressions/11.2.2-1.js
In addition to making many JSC tests fail, lack of arguments causes nearly all the editing layout tests to fail.
Geoff has made partial progress on this.
The JS and editing tests pass now. Closing.