Add test for static 8x8 gemm.

Author: chriselrod

test/gemm.jl

@@ -588,7 +588,7 @@
     if LoopVectorization.REGISTER_COUNT == 32
         @test LoopVectorization.choose_order(lsAtmulBt8) == ([:n, :m, :k], :m, :n, :m, 1, 8)
     else
-        # @test LoopVectorization.choose_order(lsAtmulBt8) == ([:n, :m, :k], :m, :n, :m, 2, 4)
+        @test LoopVectorization.choose_order(lsAtmulBt8) == ([:n, :m, :k], :m, :n, :m, 2, 4)
     end
 
     struct SizedMatrix{M,N,T} <: DenseMatrix{T}