Delete Libraries/JSInspector (#49019)

Summary:
Pull Request resolved: #49019

Removes the `JSInspector` class and its dependencies.

- This was related to the legacy `ReactCommon/inspector/` subsystem (D4021490) — which added a compat layer from JavaScriptCore to CDP for an earlier version of Chrome debugging.
- The JS components of this system (`JSInspector.js`, `NetworkAgent.js`) were added in D4021516.

`ReactCommon/inspector/` has since been deleted and these components are no longer load bearing.

- We intend to replace this logic (at least, the archaic `XHRInterceptor` behaviour, which worked at one point) with native debugger `Network` domain support in our C++ layer.

**Changes**

- Remove all modules under `Libraries/JSInspector/`.
- Remove all `XHRInterceptor` call sites.
- Remove the `JSInspector.registerAgent()` mount point in `setUpDeveloperTools.js`.
- Exclude `Libraries/Core/setUp*` from `public-api-test` (these are side-effect setup files with no exported API).

Changelog:
[General][Breaking] - Remove legacy Libraries/JSInspector modules

Reviewed By: christophpurrer

Differential Revision: D68780147

fbshipit-source-id: 3d11cc89886a91055e6b69ac6f0609c288965801

packages/react-native/Libraries/Core/setUpDeveloperTools.js

@@ -17,10 +17,6 @@ declare var console: {[string]: $FlowFixMe};
  * You can use this module directly, or just require InitializeCore.
  */
 if (__DEV__) {
-  // Set up inspector
-  const JSInspector = require('../JSInspector/JSInspector');
-  JSInspector.registerAgent(require('../JSInspector/NetworkAgent').default);
-
   // Note we can't check if console is "native" because it would appear "native" in JSC and Hermes.
   // We also can't check any properties that don't exist in the Chrome worker environment.
   // So we check a navigator property that's set to a particular value ("Netscape") in all real browsers.