refactor: update platform-browser tests to run as ESM (angular#48521)

`platform-browser` tests now run in ESM and with `.mjs` output, so
the build targets and tests need to be updated.

Here we change the `zone_event_unpatched` script to include the
`.init` suffix that will be picked up by `spec_bundle`.

Also some circular dependency tests are updated to refer to the
`.mjs` files.

PR Close angular#48521

karma-js.conf.js

@@ -40,7 +40,7 @@ module.exports = function(config) {
 
       // ZoneJS configuration needed for some event manager tests. This config could
       // affect all legacy tests but in reality is scoped to certain special tests.
-      'packages/platform-browser/test/dom/events/zone_event_unpatched_init.js',
+      'packages/platform-browser/test/dom/events/zone_event_unpatched.init.js',
 
       // Dependencies built by Bazel. See `config.yml` for steps running before
       // the legacy Saucelabs tests run.
@@ -56,7 +56,7 @@ module.exports = function(config) {
       {
         pattern: 'node_modules/@webcomponents/custom-elements/**/*.js',
         included: false,
-        watched: false
+        watched: false,
       },
 
       'node_modules/reflect-metadata/Reflect.js',

packages/platform-browser/animations/test/BUILD.bazel

@@ -3,7 +3,7 @@ load("//tools/circular_dependency_test:index.bzl", "circular_dependency_test")
 
 circular_dependency_test(
     name = "circular_deps_test",
-    entry_point = "angular/packages/platform-browser/animations/index.js",
+    entry_point = "angular/packages/platform-browser/animations/index.mjs",
     deps = ["//packages/platform-browser/animations"],
 )
 

packages/platform-browser/test/BUILD.bazel

@@ -1,3 +1,4 @@
+load("@build_bazel_rules_nodejs//:index.bzl", "js_library")
 load("//tools:defaults.bzl", "jasmine_node_test", "karma_web_test_suite", "ts_library")
 load("//tools/circular_dependency_test:index.bzl", "circular_dependency_test")
 
@@ -8,13 +9,13 @@ exports_files([
 
 circular_dependency_test(
     name = "circular_deps_test",
-    entry_point = "angular/packages/platform-browser/index.js",
+    entry_point = "angular/packages/platform-browser/index.mjs",
     deps = ["//packages/platform-browser"],
 )
 
 circular_dependency_test(
     name = "testing_circular_deps_test",
-    entry_point = "angular/packages/platform-browser/testing/index.js",
+    entry_point = "angular/packages/platform-browser/testing/index.mjs",
     deps = ["//packages/platform-browser/testing"],
 )
 
@@ -40,6 +41,11 @@ ts_library(
     ],
 )
 
+js_library(
+    name = "zone_event_unpatched_init_lib",
+    srcs = ["dom/events/zone_event_unpatched.init.js"],
+)
+
 jasmine_node_test(
     name = "test",
     bootstrap = ["//tools/testing:node"],
@@ -51,7 +57,7 @@ jasmine_node_test(
 karma_web_test_suite(
     name = "test_web",
     bootstrap = [
-        "dom/events/zone_event_unpatched_init.js",
+        ":zone_event_unpatched_init_lib",
     ],
     static_files = [
         ":static_assets/test.html",