Handle resolver extension points before activating

[sandy081]

fixes #224236

• Handle resolver extension extension points before activating it
• Only those extension points which can handle resolver extension point are handled at this stage
• Once all extensions are resolved, all extensions extension points are handled. Note that previously handled extension points of resolver extensions will not be handled due to the nature of how extension points are handled that they won't allow duplication.

[alexdima]

Nice!