[turbofan] Turn JSTypedLowering into an AdvancedReducer.

[turbofan] Turn JSTypedLowering into an AdvancedReducer.

This in turn allows usage of AdvancedReducer::ReplaceWithValue which
has access to the underlying graph reducer. It will allow us to deal
with exception continuations correctly.

R=titzer@chromium.org

Review URL: https://codereview.chromium.org/1134303003

Cr-Commit-Position: refs/heads/master@{#28468}