[lldb] Replace OptionalBool with LazyBool (#189652)

The only difference between them is that OptionalBool's third state
is "unknown" and LazyBool's is "calculate". We don't need to tell
the difference in a single context, so I've made a new eLazyBoolDontKnow
which is an alias of eLazyBoolCalculate.

GitOrigin-RevId: 2e51fdaa774be8e0d6b4d6743a2f77cdb3a71e3c