When server is under heavy load, binding with the PlaceholderBinder causes SEGFAULT!!!

[g105b]

This is a libxml issue, but it can be fixed here.

There seems to be a memory leak in libxml, similar to what's described in PHP Bug 81506.

I've managed to trace the issue down to PlaceholderBinder's use of Text::splitText. If this is done within a bindList operation, it's fine, but the scary thing is when other PHP processes do the same thing, concurrently, a SEGFAULT is caused.

This is only apparent on busy applications, but a good way of replicating is by running PHPUnit thousands of times in parallel.