Fix print test so that it passes on Julia 1.1.

Author: chriselrod

test/runtests.jl

@@ -25,7 +25,7 @@ end
     io = IOBuffer();
     println(io, LoopVectorization.operations(lsselfdot))
     s = String(take!(io))
-    @test occursin("Operation[var\"", s)
+    @test occursin("Operation[", s)
     @test occursin("s = 0", s)
     @test occursin("s = LoopVectorization.vfmadd", s)