testing/quick: Revert Alpha specific change.
testing/quick: Revert Alpha specific change.

No longer needed now that libffi supports complex types.

R=iant
CC=gofrontend-dev
https://golang.org/cl/189700043

qskycolor/gofrontend,golang/gofrontend,qskycolor/gofrontend,anlhord/gofrontend,anlhord/gofrontend,anlhord/gofrontend,qskycolor/gofrontend,qskycolor/gofrontend,qskycolor/gofrontend,qskycolor/gofrontend,golang/gofrontend,anlhord/gofrontend,golang/gofrontend,anlhord/gofrontend,anlhord/gofrontend,qskycolor/gofrontend,anlhord/gofrontend,golang/gofrontend