fix(compiler): make .ngsummary.json files idempotent (#21448)

Fixes: #21432

PR Close #21448

packages/compiler/test/aot/static_symbol_resolver_spec.ts

@@ -496,6 +496,8 @@ export class MockStaticSymbolResolverHost implements StaticSymbolResolverHost {
 
   getMetadataFor(moduleId: string): any { return this._getMetadataFor(moduleId); }
 
+  getOutputName(filePath: string): string { return filePath; }
+
   private _getMetadataFor(filePath: string): any {
     if (this.data[filePath] && filePath.match(TS_EXT)) {
       const text = this.data[filePath];

packages/compiler/test/aot/test_util.ts

@@ -386,6 +386,8 @@ export class MockAotCompilerHost implements AotCompilerHost {
     return resolved ? resolved.resolvedFileName : null;
   }
 
+  getOutputName(filePath: string) { return filePath; }
+
   resourceNameToFileName(resourceName: string, containingFile: string) {
     // Note: we convert package paths into relative paths to be compatible with the the
     // previous implementation of UrlResolver.