* Changed IL2CPP specific sections in debugger-agent.c to use the

RUNTIME_IL2CPP macro instead of IL2CPP_MONO_DEBUGGER, as the latter is
switched off on release builds to control debugger code usage.  We will
still build the debugger-agent in release, but the native linker
should strip it out.
* Stripping out code in stubs that reference code in utils::Debugger when
the debugging code is turned off.  utils::Debugger implementation is stripped
out completey in this case.

Author: Brian Raderman