perf(compiler): skip type check and emit in bazel in some cases. (#19646)

If no user files changed:
- only type check the changed generated files

Never emit non changed generated files
- we still calculate them, but don’t send them through
  TypeScript to emit them but cache the written files instead.
PR Close #19646

packages/compiler-cli/src/transformers/util.ts

@@ -11,6 +11,7 @@ import * as ts from 'typescript';
 import {DEFAULT_ERROR_CODE, Diagnostic, SOURCE} from './api';
 
 export const GENERATED_FILES = /(.*?)\.(ngfactory|shim\.ngstyle|ngstyle|ngsummary)\.(js|d\.ts|ts)$/;
+export const EXT = /(\.ts|\.d\.ts|\.js|\.jsx|\.tsx)$/;
 
 export const enum StructureIsReused {Not = 0, SafeModules = 1, Completely = 2}
 
@@ -29,3 +30,7 @@ export function createMessageDiagnostic(messageText: string): ts.Diagnostic&Diag
     source: SOURCE,
   };
 }
+
+export function isGeneratedFile(fileName: string): boolean {
+  return GENERATED_FILES.test(fileName);
+}