Reuse start position in binarySearchKey (#49641)
Reuse start position in binarySearchKey (#49641)

* Reuse start position in binarySearchKey

* Kick out early if end < position
kpreisser/TypeScript,weswigham/TypeScript,kpreisser/TypeScript,Microsoft/TypeScript,microsoft/TypeScript,weswigham/TypeScript,Microsoft/TypeScript,microsoft/TypeScript,Microsoft/TypeScript,microsoft/TypeScript,weswigham/TypeScript,kpreisser/TypeScript