Fix GetAddressOf for children of pointer ValueObjectConstResult* variables.

The original code always set the m_live_address of children of the ValueObjects that
use ValueObjectConstResultImpl backends to the parent m_live_address + child_byte_offset.
That is correct for structure types, but wrong for pointer types, since m_live_address
for a pointer type is the address of the storage for the pointer, not of the pointee.

Also added a test which was failing before this patch.