Enable AVX2 for fftw. Resolves T8235
In addition to the normal float, double, and long-double FFTW builds, this patch includes AVX2-enabled float and double libs in /usr/lib/haswell.
Test Plan: Run several applications that use FFTW, ensuring that they link against the Haswell libs (gmic, gromacs, hugin, octave).
Reviewers: Triage Team, JoshStrobl
Reviewed By: Triage Team, JoshStrobl
Subscribers: JoshStrobl, Jacalz, joebonrichie
Maniphest Tasks: T8235
Differential Revision: https://dev.getsol.us/D9641