Remove Composer support from XHProf

Summary:
See <https://github.com/phacility/xhprof/pull/40>. This is currently broken and extremely insecure.

We may want to restore it eventually, but understanding composer is very complex (no one who touched this realized that the package was owned by someone unrelated to the project who can apparently redirect it at will with no accountability). No one on the ticket seems to have any reason why this isn't totally wide open, and I haven't gotten in touch with anyone in `#composer-dev`.

Test Plan: N/A

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D10365
Update .arcconfig and acknowledge that we're the new maintainers in XHProf

Summary: Modernize this stuff a bit.

Test Plan: Ran `arc diff` to produce this diff. Read `CREDITS`.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D10366
Fix mismatched tag in contacts

Summary: See <https://github.com/phacility/xhprof/pull/42>.

Reviewed by: epriestley
XHProf: add .arclint, fix some minor issues

Summary: Add a .arclint file and fix some stray tabs and whitespace issues.

Test Plan: Built xhprof, ran tests (some failures, but preexisting).

Reviewers: chad, btrahan

Reviewed By: btrahan

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D10372
Add a basic `arc unit` test binding to XHProf

Summary:
This allows "arc unit" to more-or-less run the PHP extension tests in an approximately correct way.

Note that there are two test failures at HEAD on recent PHP, and they've been failing for some time.

Test Plan: Used `arc unit` to run some tests.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D10373
Add a failing test case for the XHProf PHP 5.5 segfault

Summary:
This adds a failing test case for the bug discussed in <https://github.com/phacility/xhprof/pull/33>.

It also adds a `bin/xhprofile` script which makes it easier to test stuff like this, by invoking the profiler on some other script. This isn't hugely useful in production but is valuable diagnostically, and helped me reduce this test case.

Test Plan:
  - Ran `arc unit` and got a failure.
  - Verified that this test passes if `class_exists()` is commented out (which makes the test not segfault).

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D10374
Fix XHProf segfault when calling internal functions in PHP 5.5

Summary:
Fixes <https://github.com/phacility/xhprof/pull/33>. Since the issue with that patch was CLA, I developed this independently.

This works because it just inlines the body of `execute_internal()`, which is nearly identical:

```
ZEND_API void execute_internal(zend_execute_data *execute_data_ptr, zend_fcall_info *fci, int return_value_used TSRMLS_DC)
{
	if(fci != NULL) {
		((zend_internal_function *) execute_data_ptr->function_state.function)->handler(fci->param_count,
				*fci->retval_ptr_ptr, fci->retval_ptr_ptr, fci->object_ptr, 1 TSRMLS_CC);

	} else {
		zval **return_value_ptr = &EX_TMP_VAR(execute_data_ptr, execute_data_ptr->opline->result.var)->var.ptr;
		((zend_internal_function *) execute_data_ptr->function_state.function)->handler(execute_data_ptr->opline->extended_value, *return_value_ptr,
					(execute_data_ptr->function_state.function->common.fn_flags & ZEND_ACC_RETURN_REFERENCE)?return_value_ptr:NULL,
					execute_data_ptr->object, return_value_used TSRMLS_CC);
	}
}
```

Test Plan: Failing test now passes. No more segfaults on PHP 5.5.8.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D10375
Fix broken XHProf unit tests

Summary:
There are two broken tests. One (007) is easy to fix. It was failing because of array-to-string conversion warnings.

Since I didn't want to add function calls because that would change the test output, I just silenced the warnings with "@".

The other test (004) was also easy to fix but I can't really explain what's going on there. Seems like it works though? It shouldn't do anything bad, since we would have generated a meaningless "???_op" otherwise.

Test Plan: Ran tests, tests passed.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D10376
Merge pull request #1 from phacility/master

Update from origin