Error, ReferenceError, etc. are given a stack property that gives a
stack trace.  Here's an example stack trace:

ReferenceError: FAIL is not defined
    at Constraint.execute (deltablue.js:527)
    at Constraint.recalculate (deltablue.js:426)
    at Planner.addPropagate (deltablue.js:703)
    at Constraint.satisfy (deltablue.js:186)
    at Planner.incrementalAdd (deltablue.js:593)
    at Constraint.addConstraint (deltablue.js:164)
    at Constraint.BinaryConstraint (deltablue.js:348)
    at Constraint.EqualityConstraint (deltablue.js:517)
    at chainTest (deltablue.js:809)
    at deltaBlue (deltablue.js:881)
    at deltablue.js:888

If Error.prepareStackTrace holds a function this function is used to
format the stack trace, for instance allowing code generators to
customize the way stack traces are reported to make them easier to
process.

Next step: performance measurements to see if it is feasible to turn
this on by default.


git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2302 ce2b1a6d-e550-0410-aec6-3dcde31c8c00