In TS 3.9 the compiler will start to wrap ES2015 classes in an IIFE to help with
tree-shaking when the class has "associated" statements.
E.g.
```ts
let PlatformLocation = /** @class */ (() => {
...
class PlatformLocation {
}
...
return PlatformLocation;
})();
```
This commit updates `Esm2015ReflectionHost` to support this format.
PR Close#36884
db4c59dad9