message: perf(ivy): speed up ngcc ivy switch processing
  Only parse the AST for ngcc ivy switch constants
  if the marker is not found in the module text.
  PR Close
diff: @@ -12,7 +12,7 @@ import {ClassMember, ClassMemberKind, CtorParameter, Decorator} from '../../../n
  import {TypeScriptReflectionHost, reflectObjectLiteral} from '../../../ngtsc/metadata';
  import {findAll, getNameText} from '../utils';
  -import {NgccReflectionHost, SwitchableVariableDeclaration, isSwitchableVariableDeclaration} from './ngcc_host';
  +import {NgccReflectionHost, PRE_NGCC_MARKER, SwitchableVariableDeclaration, isSwitchableVariableDeclaration} from './ngcc_host';
  export const DECORATORS = 'decorators' as ts.__String;
  export const PROP_DECORATORS = 'propDecorators' as ts.__String;
  @@ -205,7 +205,10 @@ export class Fesm2015ReflectionHost extends TypeScriptReflectionHost implements
  * @returns An array of variable declarations that match.
  */
  getSwitchableDeclarations(module: ts.Node): SwitchableVariableDeclaration[] {
  - return findAll(module, isSwitchableVariableDeclaration);
  + // Don't bother to walk the AST if the marker is not found in the text
  + return module.getText().indexOf(PRE_NGCC_MARKER) >= 0 ?
  + findAll(module, isSwitchableVariableDeclaration) :
  + [];
  }
  /**
  