fix(progress-spinner/testing): harness selector not matching mat-spinner selector (#19657)

The progress spinner has two variations: `mat-progress-spinner` and `mat-spinner`, but the test harness was only accounting for the former.

Fixes #19649.

Author: crisbeto

src/material/progress-spinner/testing/progress-spinner-harness.ts

@@ -14,7 +14,7 @@ import {ProgressSpinnerHarnessFilters} from './progress-spinner-harness-filters'
 /** Harness for interacting with a standard mat-progress-spinner in tests. */
 export class MatProgressSpinnerHarness extends ComponentHarness {
   /** The selector for the host element of a `MatProgressSpinner` instance. */
-  static hostSelector = 'mat-progress-spinner';
+  static hostSelector = 'mat-progress-spinner,mat-spinner';
 
   /**
    * Gets a `HarnessPredicate` that can be used to search for a `MatProgressSpinnerHarness` that

src/material/progress-spinner/testing/shared.spec.ts

@@ -26,27 +26,38 @@ export function runHarnessTests(progressSpinnerModule: typeof MatProgressSpinner
 
   it('should load all progress spinner harnesses', async () => {
     const progressSpinners = await loader.getAllHarnesses(progressSpinnerHarness);
-    expect(progressSpinners.length).toBe(2);
+    expect(progressSpinners.length).toBe(3);
   });
 
   it('should get the value', async () => {
     fixture.componentInstance.value = 50;
-    const [determinate, indeterminate] = await loader.getAllHarnesses(progressSpinnerHarness);
+    const [
+      determinate,
+      indeterminate,
+      impliedIndeterminate
+    ] = await loader.getAllHarnesses(progressSpinnerHarness);
     expect(await determinate.getValue()).toBe(50);
     expect(await indeterminate.getValue()).toBe(null);
+    expect(await impliedIndeterminate.getValue()).toBe(null);
   });
 
   it('should get the mode', async () => {
-    const [determinate, indeterminate] = await loader.getAllHarnesses(progressSpinnerHarness);
+    const [
+      determinate,
+      indeterminate,
+      impliedIndeterminate
+    ] = await loader.getAllHarnesses(progressSpinnerHarness);
     expect(await determinate.getMode()).toBe('determinate');
     expect(await indeterminate.getMode()).toBe('indeterminate');
+    expect(await impliedIndeterminate.getMode()).toBe('indeterminate');
   });
 }
 
 @Component({
   template: `
     <mat-progress-spinner mode="determinate" [value]="value"></mat-progress-spinner>
     <mat-progress-spinner mode="indeterminate"></mat-progress-spinner>
+    <mat-spinner></mat-spinner>
   `
 })
 class ProgressSpinnerHarnessTest {