adding ReflectionClass.hhi

Summary: ... reflection classes are fairly complex builtins, so
 the typechecker can deliver some value by knowing about its details.

Reviewed By: @​michalburger1

Differential Revision: D1593046
fixup VirtualHost lookup

Summary: Too many interations on the previous diff and I missed getting the real virtual host at least once so GetCurrent would return the right thing

Reviewed By: @markw65

Differential Revision: D1593559