In some cases we transform flexible type into non-flexible during
enhancement, but don't add `@EnhancedNullability` attribute to them,
which breaks consistency with K1 on IR level
This commit fixes it
^KT-65302
We are going to deprecate `WITH_RUNTIME` directive. The main reason
behind this change is that `WITH_STDLIB` directive better describes
its meaning, specifically it will add kotlin stdlib to test's classpath.
In the compiler, this function was used in psi2ir (and it affected
nullability annotations in the resulting JVM class files), in "useless
elvis with null on the right side" diagnostic checker, and in light
classes.
#KT-42650 Fixed