Completion fixes

Cleaning up some rough edges with completion list:
* completion on call/new expressions
* completions in type positions
* completions on module exports
* filtering private member completions based on location
* disable completion list in with blocks
* completion for object literal property names based on contextual type
* completions before keywords

There changes were driven by tests, so tests were all enabled in the beginning. sorry if this makes it harder to review changes.

no, cause the condition is a valid location, and you can be deep inside the condition, so I can not just say condition. I could off course use offsets to know, but this seemed like a cleaner approach.