Add Debug Tools Package for Introspection of Hooks (#14085)

* Add debug tools package

* Add basic implementation

* Implement inspection of the current state of hooks using the fiber tree

* Support useContext hooks inspection by backtracking from the Fiber

I'm not sure this is safe because the return fibers may not be current
but close enough and it's fast.

We use this to set up the current values of the providers.

* rm copypasta

* Use lastIndexOf

Just in case. I don't know of any scenario where this can happen.

* Support ForwardRef

* Add test for memo and custom hooks

* Support defaultProps resolution

Author: sebmarkbage

src/ReactTestRenderer.js

@@ -211,6 +211,7 @@ const validWrapperTypes = new Set([
   HostComponent,
   ForwardRef,
   MemoComponent,
+  SimpleMemoComponent,
   // Normally skipped, but used when there's more than one root child.
   HostRoot,
 ]);