Unordered JIT binding data

Hi,

We're running into cyclic dependencies intermittently in a large project with Guice, and figured that maintaining a specific order when configuring bindings should hopefully Guice to deterministically run into an unresolvable cycle or not.
This seems to work for the most part, but noticed that while most code in Guice carefully uses `LinkedHashSet` and `LinkedHashMap`, some use the non-ordered versions, for example https://github.com/google/guice/blob/master/core/src/com/google/inject/internal/InjectorJitBindingData.java#L18

As far as I can tell, this is not super relevant for actual bindings processing, but it was a bit surprising when trying to work out if our sorting logic works correctly when we looked through the bindings from `Injector.getAllBindings()` which had those JIT bindings in undefined order.

Would you be open to a patch changing these (and perhaps other places in the rest of the sources) from `Sets.newHashSet()` to `Sets.newLinkedHashSet()` and `Maps.newHashMap()` to `Maps.newLinkedHashMap()` ?

Thanks!