mercury 129 avx compared to avx2

[duane2064]

on my computer avx runs significantly faster than avx2, my processor is Intel(R) Core(TM) i3-6100T CPU @ 3.20GHz. maybe the labels are reversed in your release downloads page. my test was done using https://browserbench.org/MotionMark1.2. and my test with your avx, matched the performance of waterfox.