Avoid creating a new array inside doResolve.

Author: gdborton

lib/Resolver.js

@@ -692,7 +692,11 @@ class Resolver {
 			}
 			newStack.add(stackEntry);
 		} else {
-			newStack = new Set([stackEntry]);
+			// creating a set with new Set([item])
+			// allocates a new array that has to be garbage collected
+			// this is an EXTREMELY hot path, so let's avoid it
+			newStack = new Set();
+			newStack.add(stackEntry);
 		}
 		this.hooks.resolveStep.call(hook, request);