Add useful test file for loops.

Summary: Saved my life several times now.

Reviewed By: @bertmaher

Differential Revision: D1470875
Revert "Prototype of general host health monitor."

Summary: This reverts commit e29c52bace619495459fa887cc7001fec794aa89. It's
breaking the OSS version of hhvm.

Reviewed By: @alexmalyshev

Differential Revision: D1472677