initial v8 compat sketch
Initial stab at v8 Error API compat. Broke a couple of tests.
Move stack string processing to Java.
Only add a stack property if one doesn't already exist.

Also, check for undefined messages in V8StackGetter.
Ignore a strangely broken test
Make function identifiers mutable within the function scope.
Make function identifiers mutable when not in interp mode as well
Implement and use Error.stackTraceLimit and Error.prepareStackTrace.
Beef up StackElement to have appropriate properties per v8 spec.
Checkpoint for bob
Add getTypeName and getMethodName to CallSite elements.

This actually brings up an issue, which is that the things that are
currently populating a structured stack trace are not JS CallSite
objects. Rather, they are Java StackElement instances. These instances
have the same public API as a CallSite instance - but they aren't JS.
Change descibe for v8 error spec to be less verbose