Write a light with the default parameters in disabled state if
capturing a missing light.

When a light does not exist, and the app attempts to capture it in the
stateblock, a disabled light with the default light parameters is
written instead.

This reverts 92deacbe commit.

It is wrong to maintain a mapping from a constant index to a type
field, because different constant types do not share an index -
boolean constant 0 is supposed to co-exist with floating point
constant 0, not replace it. Drawprim and other code using the type
array to decide whether to look up a constant in bools, floats, or
ints is wrong - you can't make that decision based on the index.

From const%lu to C%lu for consistency (to match pshaders).