R1:a24e6deb5798

Read "$_POST" before hooking the profiler, and remove "aphront.default-application-configuration-class"

Summary:
Ref T4369. Ref T12297. Ref T13242. Ref PHI1010. I want to take a quick look at `transaction.search` and see if there's anything quick and obvious we can do to improve performance.

On `secure`, the `__profile__` flag does not survive POST like it's supposed to: when you profile a page and then submit a form on the page, the result is supposed to be profiled. The intent is to make it easier to…