Rewrite a complex expression in wxClassInfo::IsKindOf() as several statements
to avoid what looks like a gcc optimizer bug as it was dereferencing
m_baseInfo1 pointer even when it was null.
The new version is not completely equivalent to the old one as it doesn't
check for info == NULL which is not really necessary, but this is just a side
effect and doesn't affect anything, the important change is avoiding doing
everything in a single expression.
Closes#17483.
aa3acfdd15