Add 0/0 test. Closes #5061

tests/unit/src/unitstd/Math.unit.hx

@@ -8,6 +8,7 @@ Math.isNaN(Math.NaN) == true;
 Math.isNaN(Math.sqrt( -1)) == true;
 Math.NEGATIVE_INFINITY == Math.NEGATIVE_INFINITY;
 Math.POSITIVE_INFINITY == Math.POSITIVE_INFINITY;
+Math.isNaN(0/0) == true;
 // +
 Math.POSITIVE_INFINITY + Math.POSITIVE_INFINITY == Math.POSITIVE_INFINITY;
 Math.NEGATIVE_INFINITY + Math.NEGATIVE_INFINITY == Math.NEGATIVE_INFINITY;