message: refactor(compiler): add tracking comment for self-import detection
  The underlying cause of needs to be investigated and as a
  simple string compare should have been valid.
diff: @@ -305,6 +305,11 @@ export class AotCompiler {
  const arity = this._symbolResolver.getTypeArity(symbol) || 0;
  const {filePath, name, members} = this._symbolResolver.getImportAs(symbol) || symbol;
  const importModule = this._symbolResolver.fileNameToModuleName(filePath, genFilePath);
  +
  + // It should be good enough to compare filePath to genFilePath and if they are equal
  + // there is a self reference. However, ngfactory files generate to .ts but their
  + // symbols have .d.ts so a simple compare is insufficient. They should be canonical
  + // and is tracked by #17705.
  const selfReference = this._symbolResolver.fileNameToModuleName(genFilePath, genFilePath);
  const moduleName = importModule === selfReference ? null : importModule;
  