Convert ext/spl to HNI

Summary: Fixes #3947
This was a missing clone in the assignment.
Closes https://github.com/facebook/hhvm/pull/4037

Reviewed By: @ptarjan

Differential Revision: D1631910

Signature: t1:1631910:1414743838:638a61df535bbea4177c91b6adf1e9817a90e478

Pulled By: @nigelchanyk
Only escape spaces in find command

Summary: A previous refactor broke this

Reviewed By: @bhosmer

Differential Revision: D1717674

Signature: t1:1717674:1417653252:de533bf9600c453525b6d2f05e932b4f794eea67
Automatically constrain psuedomain local guards

Summary: We're already doing a guard in the LdLocPseudoMain, but since we
weren't constraining the actual guard, guard relaxation takes it away, and then
when reflowing the types with reoptimize we'd lose our local type prediction
and end up punting.  This would happen O(N^2) times.

Reviewed By: @alexmalyshev

Differential Revision: D1708551