Update aws lambda tools docs

[ericksoen]

Issue #, if available:

Description of changes:

• Update Lambda Test Tools RunTime initialization to include directory path in exception messages
• Update Lambda Test Tools docs to include image of browser tool and how to supply VS Code command line args
• Fix typo in test name

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[normj]

Thanks for the PR!