Add test for findlast (#42367)

Author: kshyatt

test/arrayops.jl

@@ -567,6 +567,7 @@ end
     @test findlast(!iszero, a) == 8
     @test findlast(a.==0) == 5
     @test findlast(a.==5) == nothing
+    @test findlast(false) == nothing # test non-AbstractArray findlast
     @test findlast(isequal(3), [1,2,4,1,2,3,4]) == 6
     @test findlast(isodd, [2,4,6,3,9,2,0]) == 5
     @test findlast(isodd, [2,4,6,2,0]) == nothing