Add norm for ModInt in tests

Author: mschauer

stdlib/LinearAlgebra/test/generic.jl

@@ -346,6 +346,8 @@ LinearAlgebra.Transpose(a::ModInt{n}) where {n} = transpose(a)
 
     # Needed for pivoting:
     Base.abs(a::ModInt{n}) where {n} = a
+    LinearAlgebra.norm(a::ModInt{n}) where {n} = a
+
     Base.:<(a::ModInt{n}, b::ModInt{n}) where {n} = a.k < b.k
 
     @test A*(lu(A, Val(true))\b) == b