The mentioned asserts did not work properly with interpreted and turbofanned functions.

To fix this issue %GetOptimizationStatus() now returns a set of flags instead of a single value.

This CL also adds more helper functions to mjsunit, like isNeverOptimize(), isAlwaysOptimize(),
isOptimized(fun), etc.

BUG=v8:5890

Review-Url: https://codereview.chromium.org/2654733004
Cr-Commit-Position: refs/heads/master@{#42703}