Refactor to improve iterations

- Use function abstractions (such as map, reduce, filter etc.) over
  for-of loops to gain benefits of having less side effects and easier
  readability.
- Enable `downLevelIterations` for writing modern code with lazy evaluation.
- Refactor for of loops to named abstractions to clearly express their
  intentions without needing to analyse the loop itself.
- Add missing cases for changes that had no tests.

tests/unit/stubs/FunctionCallArgumentCollectionStub.ts

@@ -14,9 +14,8 @@ export class FunctionCallArgumentCollectionStub implements IFunctionCallArgument
   }
 
   public withArguments(args: { readonly [index: string]: string }) {
-    for (const parameterName of Object.keys(args)) {
-      const parameterValue = args[parameterName];
-      this.withArgument(parameterName, parameterValue);
+    for (const [name, value] of Object.entries(args)) {
+      this.withArgument(name, value);
     }
     return this;
   }