Fix tests prior to removing AAWH::fromDarray and ::fromVarray

Fix tests prior to removing AAWH::fromDarray and ::fromVarray

Summary:
Some tests were deleted:
hphp/test/slow/dv_array/await_all_from_varray.php and hphp/test/slow/dv_array_hack_arr/await_all_from_varray.php doesn't do anything that we don't have other tests covering for AAWH::fromVec
hphp/test/slow/async/streams/socket-pair.php.disabled has been disabled for a long time, and there is no way to safely re-enable it (it wants to be able to listen on a port, which is inherently racy in unit tests); just delete it instead.

hphp/test/slow/hack_arr_compat/gena.php was brought up to date with www

The remaining tests had ::fromVarray/::fromDarray parts either deleted (if they duplicate other parts testing ::fromVec/::fromDict) or converted to ::fromVec/::fromDict if they aren't duplicates.

Reviewed By: jano

Differential Revision: D34818480

fbshipit-source-id: 9d4ad336237c898934fed0c3751bdd92e4c1e8f7