Adjust the iteration behavior of the shimMap (used for IE 11) to visit values that are added while forEach is running.
Adjust the iteration behavior of the shimMap (used for IE 11) to visit values that are added while forEach is running.

Fixes #26090

nojvek/TypeScript,nojvek/TypeScript,Microsoft/TypeScript,kpreisser/TypeScript,nojvek/TypeScript,microsoft/TypeScript,RyanCavanaugh/TypeScript,SaschaNaz/TypeScript,SaschaNaz/TypeScript,microsoft/TypeScript,SaschaNaz/TypeScript,nojvek/TypeScript,kpreisser/TypeScript,kpreisser/TypeScript,kitsonk/TypeScript,alexeagle/TypeScript,RyanCavanaugh/TypeScript,alexeagle/TypeScript,weswigham/TypeScript,SaschaNaz/TypeScript,weswigham/TypeScript,alexeagle/TypeScript,weswigham/TypeScript,Microsoft/TypeScript,microsoft/TypeScript,Microsoft/TypeScript,kitsonk/TypeScript,minestarks/TypeScript,RyanCavanaugh/TypeScript,kitsonk/TypeScript,minestarks/TypeScript,minestarks/TypeScript