build: remove release packaging gulp code (#17668)

* build: remove release packaging gulp code

* Removes the code that was responsible for building the
release packages through Gulp.
* Removes build tsconfig files that were needed to detect
secondary entry-points in the gulp package-tools
* Switches legacy Karma tests to run with Ivy.

*Note*: still need to keep small parts of the package-tools
since we still cannot run tests with Bazel in Saucelabs/BS.
Also we wanted to keep `gulp test:static / gulp test` for now.

* fixup! build: remove release packaging gulp code

Fixup import test

Author: devversion

package.json

@@ -41,8 +41,6 @@
     "stylelint": "stylelint \"src/**/*.+(css|scss)\" --config .stylelintrc.json --syntax scss"
   },
   "version": "9.0.0-rc.1",
-  "requiredAngularVersion": "^9.0.0-0 || ^10.0.0-0",
-  "requiredMDCVersion": "^4.0.0",
   "dependencies": {
     "@angular/animations": "^9.0.0-rc.1",
     "@angular/common": "^9.0.0-rc.1",

src/cdk-experimental/dialog/tsconfig-build.json

@@ -1,30 +1,26 @@
-// TypeScript config file that extends the default build tsconfig file. This config is used to
-// also compile the unit-test files. Since the code will run inside of the browser, the target is
-// set to ES5. Also the format needs to be CommonJS for Karma.
 {
-  "extends": "./tsconfig-build",
+  "extends": "../bazel-tsconfig-build.json",
   "compilerOptions": {
+    "baseUrl": ".",
+    "outDir": "../../dist/packages/cdk-experimental",
+    "rootDir": ".",
+    "rootDirs": [
+      ".",
+      "../../dist/packages/cdk-experimental"
+    ],
     "importHelpers": false,
     "module": "commonjs",
     "target": "es5",
     "types": ["jasmine"],
+    "experimentalDecorators": true,
+    "emitDecoratorMetadata": true,
     "paths": {
       "@angular/cdk/*": ["../../dist/packages/cdk/*"],
       "@angular/cdk-experimental/*": ["./*"]
     }
   },
-  "angularCompilerOptions": {
-    "skipTemplateCodegen": true,
-    "emitDecoratorMetadata": true,
-
-    // Unset options inherited from tsconfig-build
-    "annotateForClosureCompiler": false,
-    "flatModuleOutFile": null,
-    "flatModuleId": null,
-  },
   "include": [
-    // Include the index.ts for each secondary entry-point
-    "./*/index.ts",
+    "**/index.ts",
     "**/*.spec.ts"
   ],
   "exclude": [