fix(ivy): ngcc should process undecorated base classes (#30821)

Currently undecorated classes are intentionally not processed
with ngcc. This is causing unexpected behavior because decorator
handlers such as `base_def.ts` are specifically interested in class
definitions without top-level decorators, so that the base definition
can be generated if there are Angular-specific class members.

In order to ensure that undecorated base-classes work as expected
with Ivy, we need to run the decorator handlers for all top-level
class declarations (not only for those with decorators). This is similar
to when `ngtsc` runs decorator handlers when analyzing source-files.

Resolves FW-1355. Fixes https://github.com/angular/components/issues/16178

PR Close #30821

packages/compiler-cli/ngcc/test/rendering/renderer_spec.ts

@@ -234,6 +234,38 @@ describe('Renderer', () => {
                .toEqual(`{ type: Directive, args: [{ selector: '[a]' }] }`);
          });
 
+      it('should render classes without decorators if handler matches', () => {
+        const {renderer, decorationAnalyses, switchMarkerAnalyses, privateDeclarationsAnalyses,
+               testFormatter} = createTestRenderer('test-package', [{
+                                                     name: '/src/file.js',
+                                                     contents: `
+              import { Directive, ViewChild } from '@angular/core';
+              
+              export class UndecoratedBase { test = null; }
+              
+              UndecoratedBase.propDecorators = {
+                test: [{
+                  type: ViewChild,
+                  args: ["test", {static: true}]
+                }],
+              };
+            `
+                                                   }]);
+
+        renderer.renderProgram(
+            decorationAnalyses, switchMarkerAnalyses, privateDeclarationsAnalyses);
+
+        const addDefinitionsSpy = testFormatter.addDefinitions as jasmine.Spy;
+        expect(addDefinitionsSpy.calls.first().args[2])
+            .toEqual(
+                `UndecoratedBase.ngBaseDef = ɵngcc0.ɵɵdefineBase({ viewQuery: function (rf, ctx) { if (rf & 1) {
+        ɵngcc0.ɵɵstaticViewQuery(_c0, true, null);
+    } if (rf & 2) {
+        var _t;
+        ɵngcc0.ɵɵqueryRefresh(_t = ɵngcc0.ɵɵloadViewQuery()) && (ctx.test = _t.first);
+    } } });`);
+      });
+
       it('should call renderImports after other abstract methods', () => {
         // This allows the other methods to add additional imports if necessary
         const {renderer, decorationAnalyses, switchMarkerAnalyses, privateDeclarationsAnalyses,