Ensure `Thread.currentThread().getContextClassLoader()` returns the same
classloader for all types of initialization.
Prior to this commit, `JettyEmbeddedWebAppContext` would return a
different classloader when initializing Servlet and Filter classes. This
was due to the fact that our `deferredInitialize()` method has called
outside of a `getContext().call(...)`.
Fixes gh-37649
Co-authored-by: Phillip Webb <phil.webb@broadcom.com>
98c11bb5df