migrate many callsites from Config::GetFoo to Config::Bind

Summary: codemod -m --extensions cpp '([^ ]*)\s*=\s*Config::Get(Bool|String|Byte|UByte|Int16|UInt16|Int32|UInt32|Int64|UInt64)[(]ini,\s*([^\s]*),\s*([^\s]*)[)];' 'Config::Bind(\1, ini, \2, \3);'

and some manual rebasing to current behavior

Reviewed By: @ptarjan

Differential Revision: D1371389
Add hhvm.pcre.jit ini flag to check build config

Summary: Want the benchmark script to check this.

Reviewed By: @oyamauchi

Differential Revision: D1545388