refactor(bazel): convert most ts_library to ng_module (#22176)

This is necessary so we can produce ng metadata for our packages that are published as libraries

PR Close #22176

packages/core/testing/BUILD.bazel

@@ -1,10 +1,9 @@
 package(default_visibility = ["//visibility:public"])
 
-load("//tools:defaults.bzl", "ts_library")
+load("//tools:defaults.bzl", "ng_module")
 
-ts_library(
+ng_module(
     name = "testing",
-    testonly = 1,
     srcs = glob(["**/*.ts"]),
     module_name = "@angular/core/testing",
     deps = [

packages/core/testing/src/test_compiler.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {Compiler, CompilerOptions, Component, ComponentFactory, Directive, Injector, NgModule, Pipe, Type} from '@angular/core';
+import {Compiler, CompilerOptions, Component, ComponentFactory, Directive, Injectable, Injector, NgModule, Pipe, Type} from '@angular/core';
 
 import {MetadataOverride} from './metadata_override';
 
@@ -19,6 +19,7 @@ function unimplemented(): any {
  *
  * @experimental
  */
+@Injectable()
 export class TestingCompiler extends Compiler {
   get injector(): Injector { throw unimplemented(); }
   overrideModule(module: Type<any>, overrides: MetadataOverride<NgModule>): void {