build: upgrade bazel rules to latest (#20768)

Add enough BUILD files to make it possible to
`bazel build packages/core/test`

Also re-format BUILD.bazel files with Buildifier.
Add a CI lint check that they stay formatted.

PR Close #20768

packages/platform-browser/testing/BUILD.bazel

@@ -0,0 +1,16 @@
+package(default_visibility = ["//visibility:public"])
+
+load("@build_bazel_rules_typescript//:defs.bzl", "ts_library")
+
+ts_library(
+    name = "testing",
+    testonly = 1,
+    srcs = glob(["**/*.ts"]),
+    module_name = "@angular/platform-browser/testing",
+    tsconfig = "//packages:tsconfig",
+    deps = [
+        "//packages/core",
+        "//packages/platform-browser",
+        "@rxjs",
+    ],
+)