fix(ivy): platform module bootstrap does not resolve resources (#29083)

Currently with ViewEngine, if someone runs the platform's
`bootstrapModule` method in order to boostrap a module in
JIT mode, external component resources are properly resolved
*automatically*.

Currently with Ivy, the developer would need to manually call
`resolveComponentResources` in order to asynchronously fetch
the determined external component resources. In order to make
this backwards compatible with ViewEngine, and also since
platforms can already specify a `ResourceLoader` compiler
provider, we need to automatically resolve all external
component resources on module bootstrap.

--

Since the `ResourceLoader` is part of the `@angular/compiler`,
because ViewEngine performed the factory creation in the compiler,
we can't access the `ResourceLoader` token from within core.

In order to workaround this without introducing a breaking change,
we just proxy the `ResourceLoader` token to `core` through the
compiler facade. In the future, we should be able to move the
`ResourceLoader` to core when ViewEngine code no longer exists in
the `@angular/compiler`.

PR Close #29083

packages/core/src/metadata/resource_loading.ts

@@ -99,6 +99,10 @@ export function clearResolutionOfComponentResourcesQueue() {
   componentResourceResolutionQueue.clear();
 }
 
+export function isComponentResourceResolutionQueueEmpty() {
+  return componentResourceResolutionQueue.size === 0;
+}
+
 function unwrapResponse(response: string | {text(): Promise<string>}): string|Promise<string> {
   return typeof response == 'string' ? response : response.text();
 }