all: replace internal rand shim with math/rand/v2

lapack/testlapack/dlange.go

@@ -6,10 +6,10 @@ package testlapack
 
 import (
 	"math"
+	"math/rand/v2"
 	"testing"
 
 	"gonum.org/v1/gonum/blas/blas64"
-	"gonum.org/v1/gonum/internal/rand"
 	"gonum.org/v1/gonum/lapack"
 )
 
@@ -18,7 +18,7 @@ type Dlanger interface {
 }
 
 func DlangeTest(t *testing.T, impl Dlanger) {
-	rnd := rand.New(rand.NewSource(1))
+	rnd := rand.New(rand.NewPCG(1, 1))
 	for _, test := range []struct {
 		m, n, lda int
 	}{