Autocomplete - Pass Typing_env to AutocompleteService when completing ID

Summary: This makes it so that when we're completing inside a function call param and completing a function name, we get ranked results.

Reviewed By: @jwatzman

Differential Revision: D1413659
Implemented xdebug_call_class

Summary: Depends on D1388555.

This diff implements the xdebug function xdebug_call_class.
If function Foo::g calls function f and function f calls xdebug_call_class,
the class name "Foo" is returned.

Reviewed By: @fredemmott

Differential Revision: D1388750
Fix more "newtype as" issues

Summary: @dlreeves found a few more places that we need to unwrap a
`newtype X as Y`. This is probably going to be whackamole for a little
while unfortunately. @pikatchu suggested I add the `Tabstract` case above
any `Tgeneric` case, but there's a //lot// of them, and I think this
approach is somewhat less messy.

Reviewed By: @pikatchu

Differential Revision: D1414279
Fix DataBlock overflows

Summary: The relocation code was bypassing runtime checks for overflowing
DataBlocks in opt builds (there was still an assert for dbg builds). This
rewrites it to relocate into a DataBlock instead of into a range of memory.

Reviewed By: @ottoni

Differential Revision: D1415998
move temp dir base name to var

Summary: Move temp directory base name to config variable.

Reviewed By: @jwatzman

Differential Revision: D1416220
Fix array_multisort to allow for first arg that can't be taken by reference

Summary: array_multisort accepts any non-zero number of arguments, and for all of
its varargs (everything except the first arg) it tries to take each
vararg by reference but allows varargs that can't be taken by reference
(for example, an array literal). However, HHVM's implementation of
array_multisort erroneously fatals (if called directly) or warns (if called
via call_user_func_array()) if its first arg cannot be taken by reference,
which differs from PHP5.

This diff fixes HHVM's implementation of array_multisort to allow its first
arg to be something that can't be taken by reference without raising any
warnings. It also fixes the "call_user_func_array('array_multisort', $args)"
use case so that it does not raise a warning if the first element in $args
is not a reference.

Closes #1486

Reviewed By: @ptarjan

Differential Revision: D1412141