[lldb] [Reproducer] Move SBRegistry registration into declaring files

Move SBRegistry method registrations from SBReproducer.cpp into files
declaring the individual APIs, in order to reduce the memory consumption
during build and improve maintainability.  The current humongous
SBRegistry constructor exhausts all memory on a NetBSD system with 4G
RAM + 4G swap, therefore making it impossible to build LLDB.

Differential Revision: https://reviews.llvm.org/D59427

llvm-svn: 356481