Generated files catch-up.  Missed these in a prior push.
Fix incorrect assumption in TranslatorX64::useTvResult

"foo()->bar += <expr>;" can produce an instruction where the
bottommost stack input is not the first stack input in
ni.inputs. useTvResult needs to be tolerant of this. I also fixed a
typo in emitPropGeneric that I found while working on literal support.
Create new bytecode NewTuple for creating simple arrays

A very common pattern for array-creation is array(<expr>,...) where
no keys are given.  Capitalize on it with an opcode dedicated to that
pattern.  Limit the arity to avoid excessively big operand stacks.
Fixed bugs in property accesses, conversion and simplification, and added additional runtime asserts to generated code.

Fixed a bug in static property accesses where we passed the
wrong parameter to SPropCache::lookup. Fixed some code gen problems in
type conversions. Added a check stack that checks top of stack contents
for bad ref counted values. This is called on a function return.
Fixed a refcounting bug in int-to-string casting and CSE'ing of instructions
that produce or consume reference count.
Add low_{malloc,free}().

Add low_{malloc,free}(), which use jemalloc functionality to allocate
objects in low memory (via sbrk(2)).  Use these functions to allocate
Unit, Class, Func, and static StringData objects, so that the TC can use
more compact addressing modes when burning in references to them.
String equality can be improved.

Ben Maurer pointed out an opportunity this morning while looking at perf top
output: eq_str_str was a little too quick to resort to memcmp. It was relying
on the trinary StringData::compare(), which falls back to
memcmp(a, b, min(len1, len2)) once the easy cases have been exhausted.

If we don't care about which direction the inequality goes (as for ==, !=,
etc.), we can first test length. We apparently test unequal strings frequently
enough for this to be profitable. I'll also try comparing hashes.

This is a little rough as-is; for instance, the short-circuit test for
identical pointers in eq_str_str might not really be helping.
Fix private properties not showing up in the debugger.
Disable direct trace jump when jcc is eliminated during codegen

When a conditional jump is eliminated during codegen, turn off
the direct jump optimization for the associated exits by setting
the jump's data field to kIRDirectJumpInactive
When storing to locals, always store the type for strings

For string-typed locals, we can't skip storing the type even when the
old and new types are the same at compile time. That's because the
guards don't distinguish between static and non-static strings, so
translations should be general to handle both cases.

Also added checks for non-generic cells in SpillStack.
NewTuple should not be trying to allocate registers.

Mark NewTuple as manually allocating registers, since we don't need any.
Revert prefetcht2 in GarbageList::maybePop()
Support stream_resolve_include_path()

Code copy of fb_could_include(), but returning
the string rather than casting to bool.
Fix for hphp_gettid() implementation

Redid the system files update, and now it builds.
Debugger fixes/cleanup

The various debugger classes with worker threads need to wait
for the worker thread to finish before destroying the AsyncFunc
object. I also added a bunch of logging to make figuring out exactly
what went wrong easier.
Added Conv string->int

Implemented cgConv for src:string, res:int
Actually enable JIT by default in server/daemon/replay modes

Previous diff missed that RuntimeOption::ExecutionMode
was being set *after* the config file was loaded, so checking
ExecutionMode always yielded an empty string (and thus not srv).

Also removed from unnecessary duplicate code.