Fix #1737 "getObjectByEffectiveId slow with large form"

- searching in controls first is usually a good idea
- in the case of handlers, only controls are searched this way
- cuts time in half for a very large form
For #1738: faster class splitting

- can yield a 30% speedup on large Form Runner automatic PDF output
- see https://github.com/orbeon/flyingsaucer/commit/96d9111e5fe006d000ff45811e78f5a84c404ae8