Update third-party hash for libmbfl cmake fix

Summary: See: https://github.com/hhvm/hhvm-third-party/commit/1d387ce2a33fc75d25c7ee3318537296387d8799

Reviewed By: @paulbiss

Differential Revision: D1747030

Signature: t1:1747030:1418864344:44cf2ea827cccd2c2fd4a926352855ce7bc975b9
Fix Memcached::setOption for OPT_LIBKETAMA_COMPATIBLE

Summary: The current implementation is missing an if-statement which causes
the option to be unset even when a truthy value is passed in. The comment
directly above this block describes the correct behavior. See the original PHP
implementation for reference: http://goo.gl/7p7WqP. A new constant
Memcached::DISTRIBUTION_CONSISTENT_KETAMA is added for the sake of testing.

Closes https://github.com/facebook/hhvm/pull/4364

Reviewed By: @paulbiss

Differential Revision: D1710109

Signature: t1:1710109:1418880558:9a97113ad941927c06ca0ed8389f2208b18eca86
Actually get the realpath first thing when searching for a file.

Summary: D1729338 fixed a subtle bug, but not completely. We didn't handle the case where
the test runner was run in the exact same directory as the test in question. If we
did, it would still come in as `.` if `dirname()` was used beforehand, which is
probably not desired behavior. So move the call to `realpath()` to before the
`while()` loop and all cases should now be handled.

{sync, type="child", parent="internal", parentrevid="1742941", parentrevfbid="866765913387291", parentdiffid="5964829"}

Reviewed By: @paulbiss

Differential Revision: D1742941

Signature: t1:1742941:1418878079:1499d0d009589f7a47a1f1a04e08619c2813b673
Explicitly narrow Bool dests when appropriate in vasm

Summary: This ensures that the destination register for instructions like
t5:Bool = AssertType<Bool> t4:Cell will have the right type (i8) in llvm, and
it shouldn't affect the code generated by vasm-x64.

Reviewed By: @jasone

Differential Revision: D1746194

Signature: t1:1746194:1418849552:9c866c2c7ff77fc6333af6576687c96a13ebcc7f
Rename Vunit::cpool to constants

Reviewed By: @alexmalyshev

Differential Revision: D1746483
All test skips shouldn't be clowntown

Summary: The tests exist; it is just that we skip them. That is different than
trying to run the runner on no tests at all.

{sync, type="child", parent="internal", parentrevid="1747947", parentrevfbid="1634072033486914", parentdiffid="5989133"}

Reviewed By: @fredemmott

Differential Revision: D1747947

Signature: t1:1747947:1418907361:4bf41aab6ec48a15de6fa2acb21ab49734c6f037
Add PHP lang spec tests to HHVM test suite

Summary: We have wanted to do this for a while, so now I am. These are
the PHP lang spec tests. I used the PHP 5.x import script
as a model to get the tests. But we don't have `good`, `bad`, etc.
Instead we have a global `config.skipif` with the tests that are failing
and we put a comment as to why they are failing.

Key file changes (other than new tests and expect files):

```
hphp/test/README.md
hphp/test/run
hphp/test/spec/.gitattributes
hphp/test/spec/.gitignore
hphp/test/tools/find_non_ascii_files.php
hphp/test/tools/import_spec_test.py
hphp/test/spec/config.skipif  (autogenerated by import_spec_test.py)
```

Reviewed By: @paulbiss

Differential Revision: D1718437
fix typo in fastlz library cmake variable

Summary: i guess my console font didn't help me notice this one :(
Closes https://github.com/facebook/hhvm/pull/4475

Reviewed By: @paulbiss

Differential Revision: D1745333

Signature: t1:1745333:1418921775:14f4f9664b8e905394f432396081ef90e4528fc5
(Cleanup) fb_thrift_unserialize

Summary: Discovered while typing `i fb_unserialize` in `hphpd`. This function
doesn't exist. TAO has more lovely references to it, and to files that
don't exist. Fun.

Reviewed By: @markw65

Differential Revision: D1747154

Signature: t1:1747154:1418922414:ba13c725d7341bb493acc67c1398a0c3401a4808
Manually inline unserializeKey

Summary: This just bounces execution from type-variant to variable-unserializer
and back for no really good reason.  It's only used in two places, so just do
it inline.

Reviewed By: @jdelong, @alexmalyshev

Differential Revision: D1747600

Signature: t1:1747600:1418869968:22e2abe342d2cd4730fb58a953096b25144da6ff