This patch pushes the error handling boundary for the GetBitSize()
methods from Runtime into the Type and CompilerType APIs. This makes it
easier to diagnose problems thanks to more meaningful error messages
being available. GetBitSize() is often the first thing LLDB asks about a
type, so this method is particularly important for a better user
experience.
rdar://145667239
The vast majority of `SyntheticChildrenFrontEnd` subclasses provide
children, and as such implement `MightHaveChildren` with a constant
value of `true`. This change makes `true` the default value. With this
change, `MightHaveChildren` only needs to be implemented by synthetic
providers that can return `false`, which is only 3 subclasses.
ValueObject is part of lldbCore for historical reasons, but conceptually
it deserves to be its own library. This does introduce a (link-time) circular
dependency between lldbCore and lldbValueObject, which is unfortunate
but probably unavoidable because so many things in LLDB rely on
ValueObject. We already have cycles and these libraries are never built
as dylibs so while this doesn't improve the situation, it also doesn't
make things worse.
The header includes were updated with the following command:
```
find . -type f -exec sed -i.bak "s%include \"lldb/Core/ValueObject%include \"lldb/ValueObject/ValueObject%" '{}' \;
```
These proxies are returned by operator[](...). These proxies all
"behave" the same. They store a pointer to the data of the valarray they
are a proxy for and they have an internal array of indices. This
internal array is considered its contents.
