Defer functions enclosed in all contexts. Support deferral of functions enclosed in scopes other than function body and function expression scope -- in particular, ES6-style lexical scopes and parameter scopes. This requires changing ScopeInfo so that it is associated with a single scope rather than a function body. Instead of carrying per-function information for body/var scope, parameter scope, and function expression scope, ScopeInfo will describe one scope, with a value identifying the scope type, a pointer to the FunctionInfo that contains it, and a pointer to the enclosing ScopeInfo.. A FunctionProxy will point to the ScopeInfo that is the nearest enclosing scope. At parse time, we will reconstitute the closure environment by walking the list of enclosing ScopeInfo's. The code that allowed redeferral to work around the context limitation of deferring parsing is deleted, and the OptimizeBlockScope feature is off by default, as it doesn't play well with this new logic and isn't required to make (re-)deferral effective. (We will want to revisit it.)