This diff suppresses the output of C++ for the "pure" classes defined in
system/classes, and it rips out all the uses of MethodCallPackage (except
for the i_* and ifa_* helpers, which we can go after separately).
Also cleans up a bunch of "if (hhvm)" and "#ifdef HHVM" checks in builtin_functions.cpp,
systemlib.cpp, object_data.cpp, and class_info.cpp (and the corresponding .h files).
Note that this does not completely remove the generated C++ files. We
still generate code for the PHP files in "system/globals" and we still
generate the g_class_map (because the VM needs g_class_map at startup
when it creates Class's for the extensions). We also still have the
dynamic_func_table/dynamic_class_table stuff, MethodCallPackage, and
the i_* and ifa_* helpers to support invoke_builtin() (which is still
used by the compiler).
This change is mostly for FB internal organizational reasons.
Building is not effected beyond the fact that the target now
lands in hphp/hhvm/hhvm rather than src/hhvm/hhvm.
andrewparoski