build: extract interface and util sub compilation from core (#28028)

PR Close #28028

packages/core/src/interface/BUILD.bazel

@@ -0,0 +1,16 @@
+package(default_visibility = [
+    "//packages/core:__subpackages__",
+    "//tools/public_api_guard:__pkg__",
+])
+
+load("//tools:defaults.bzl", "ts_library")
+
+ts_library(
+    name = "interface",
+    srcs = glob(
+        [
+            "*.ts",
+        ],
+    ),
+    module_name = "@angular/core/interface",
+)

packages/core/src/interface/type.ts

@@ -0,0 +1,29 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+/**
+ * @description
+ *
+ * Represents a type that a Component or other object is instances of.
+ *
+ * An example of a `Type` is `MyCustomComponent` class, which in JavaScript is be represented by
+ * the `MyCustomComponent` constructor function.
+ *
+ * @publicApi
+ */
+export const Type = Function;
+
+export function isType(v: any): v is Type<any> {
+  return typeof v === 'function';
+}
+
+export interface Type<T> extends Function { new (...args: any[]): T; }
+
+export type Mutable<T extends{[x: string]: any}, K extends string> = {
+  [P in K]: T[P];
+};