Replace String.valueOf(float) and String.valueOf(double)

h2/src/main/org/h2/value/ValueDouble.java

@@ -118,7 +118,7 @@ public class ValueDouble extends Value {
 
     @Override
     public String getString() {
-        return String.valueOf(value);
+        return Double.toString(value);
     }
 
     @Override

h2/src/main/org/h2/value/ValueFloat.java

@@ -119,7 +119,7 @@ public class ValueFloat extends Value {
 
     @Override
     public String getString() {
-        return String.valueOf(value);
+        return Float.toString(value);
     }
 
     @Override