add (and use) EJSVAL_TO_BOOLEAN_OBJECT
map2.js needs a special expected-out file because we report (correctly) [object Map], while node 0.10.25 reports [object Object]
Number.prototype.clz/Math.clz32 rework.

the latest draft drops Number.prototype.clz.  our implementation of Math.clz32 was
also broken (it only worked if you passed it > 1 arguments).  Fix that issue, and
also use __builtin_clz if it's available.