fix(@angular/build): setup unit-test polyfills before TestBed init

To ensure that Zone.js is fully setup and patched prior to the use of TestBed,
the setup file order for the `vitest` runner of the `unit-test` builder
has been swapped. This is particularly relevant for `fakeAsync` which
has a module level statement that attempts to capture the `Zone` instance.
If Zone.js is not setup at that point, fakeAsync will fail to function in
tests.

Author: clydin

packages/angular/build/src/builders/unit-test/builder.ts

@@ -194,7 +194,7 @@ export async function* execute(
   // Add setup file entries for TestBed initialization and project polyfills
   const setupFiles = ['init-testbed.js'];
   if (buildTargetOptions?.polyfills?.length) {
-    setupFiles.push('polyfills.js');
+    setupFiles.unshift('polyfills.js');
   }
 
   try {