`globals` are not exposed in the Debugger

[elliette]

global Dart variables are not currently shown in the debugger.

@nshahan did some investigation and found we will likely need to request the globals for the current library. In Chrome DevTools, they are discoverable in a closure with the library name:

[nshahan]

I'm anticipating there are some changes coming soon to the way DDC represents library global methods, getters, setters, and fields to support hot reload. This will likely need to be coordinated with dwds once we settle on a representation that works well. One idea is to use the same representation we use for class static methods, getters, setters, and fields so there might be an opportunity to reduce some of the logic required.