stop prefixing test to TEST_PATH

It is good design to not repeat things that are redundant,
but this keeps anoying me that I can't tab complete this.
no-one should be used to the syntax yet so now is the time to change it.
Remove HPHP_LIB as a place to find systemlib.php
Shut down if we lose a LightProcess child

This should only happen if there's a bug in our code and the
child process crashes, or if one gets killed by the OOM killer. In
either case, it's probably not safe for the parent process to continue
uninterrupted, so shut down.
Add a few traces in annotation.cpp
Use hphpc-provided property types in CGetM prediction

We still need to check that the types aren't null, but we can
continue traces with a side-exit guard.
Allocate unit bytecode and metadata in a read-only memory region

Only in RepoAuthoritative mode, where units can't be
deallocated.  I have a semi-reproducable bug where a unit's m_bc
region is getting corrupted (only occasionally in perflab).
Presumably moving it out of the malloc'd heap will make the bug
corrupt something else, so this probably doesn't really help much, but
it seemed like having a separate region for some cold, read-only,
process-lifetime metadata might make sense.
Disabled non-refcounted locals optimization

It's still flaky, and I'm hitting asserts related to it on
trunk right now.
HHIR mod.
Implement FPushCuf* in hhir

This handles almost all the cases tx64 does. It takes a slow
exit when a Class or Func that was around at translation time doesn't
exist at runtime, which never happens in prod (as of right now).
kill TAINTED code

While I was working on the TestCodeRun refactor I found two tests about Tainted code. I looked into it and coulnd't get HHVM to compile with TAINTED=1. Then I checked and none of the extension functions we exposed about tainting were used in WWW. Scratching my head I asked, @srenfro and @jdelong, who  thought it was dead. So I killed this zombie.
Separate handwritten assembly helpers into a .S file

This feels like a cleaner approach. It separates code that's
arch-specific by nature, lets us avoid all the ugly quote marks and \n
sequences, and lets your editor do real syntax highlighting of asm.