add let to define i

Libraries/Utilities/MatrixMath.js

@@ -640,7 +640,7 @@ const MatrixMath = {
     // Now get scale and shear.
     // 'row' is a 3 element array of 3 component vectors
     const row = [];
-    for (i = 0; i < 3; i++) {
+    for (let i = 0; i < 3; i++) {
       row[i] = [matrix[i][0], matrix[i][1], matrix[i][2]];
     }
 
@@ -678,7 +678,7 @@ const MatrixMath = {
     // is -1, then negate the matrix and the scaling factors.
     const pdum3 = MatrixMath.v3Cross(row[1], row[2]);
     if (MatrixMath.v3Dot(row[0], pdum3) < 0) {
-      for (i = 0; i < 3; i++) {
+      for (let i = 0; i < 3; i++) {
         scale[i] *= -1;
         row[i][0] *= -1;
         row[i][1] *= -1;