Move lambda resolution to runtime

This has a very positive impact on precompiled output size, particularly for known-helpers cases, and little or no impact on the throughput numbers.

lib/handlebars/compiler/javascript-compiler.js

@@ -377,11 +377,9 @@ JavaScriptCompiler.prototype = {
   // If the `value` is a lambda, replace it on the stack by
   // the return value of the lambda
   resolvePossibleLambda: function() {
-    this.aliases.functionType = '"function"';
+    this.aliases.lambda = 'this.lambda';
 
-    this.replaceStack(function(current) {
-      return "typeof " + current + " === functionType ? " + current + ".apply(depth0) : " + current;
-    });
+    this.push('lambda(' + this.popStack() + ', depth0)');
   },
 
   // [lookup]

lib/handlebars/runtime.js

@@ -50,6 +50,10 @@ export function template(templateSpec, env) {
 
   // Just add water
   var container = {
+    lambda: function(current, context) {
+      return typeof current === 'function' ? current.call(context) : current;
+    },
+
     escapeExpression: Utils.escapeExpression,
     invokePartial: invokePartialWrapper,