feat(cdk-experimental/tabs): add setDefaultState and unit tests, refactor the content children strategy (angular#31374)

Author: ok7sai

src/cdk-experimental/tabs/BUILD.bazel

@@ -1,4 +1,4 @@
-load("//tools:defaults.bzl", "ng_project")
+load("//tools:defaults.bzl", "ng_project", "ng_web_test_suite", "ts_project")
 
 package(default_visibility = ["//visibility:public"])
 
@@ -16,3 +16,22 @@ ng_project(
         "//src/cdk/bidi",
     ],
 )
+
+ts_project(
+    name = "unit_test_sources",
+    testonly = True,
+    srcs = [
+        "tabs.spec.ts",
+    ],
+    deps = [
+        ":tabs",
+        "//:node_modules/@angular/core",
+        "//:node_modules/@angular/platform-browser",
+        "//src/cdk/testing/private",
+    ],
+)
+
+ng_web_test_suite(
+    name = "unit_tests",
+    deps = [":unit_test_sources"],
+)