TypescriptLambdaHandlerSearch performance evaluation

**Is your feature request related to a problem? Please describe.**

#142 , #140

**Describe the solution you'd like**

`TypescriptLambdaHandlerSearch.findCandidateLambdaHandlers` uses the Typescript engine to look for code that could serve as javascript handlers for Lambda Functions. A performance evaluation should be run on large files (10,000+ lines of code, many functions) so we are aware of any impact on the UI, or how responsive the calling code (such as codeLens providers) will be.

**Describe alternatives you've considered**

**Additional context**

Start by locating TypescriptLambdaHandlerSearch.findCandidateLambdaHandlers and review related issues #142 and #140. Benchmark it on files with 10,000+ lines and many functions, then record whether the UI and callers such as codeLens providers remain responsive.

Written by the indexing model from the issue text.