remove implicit PString -> String cast

Author: timfel

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/truffle/PythonArithmeticTypes.java

@@ -28,7 +28,6 @@
 import com.oracle.graal.python.builtins.objects.cext.PythonNativeClass;
 import com.oracle.graal.python.builtins.objects.cext.PythonNativeObject;
 import com.oracle.graal.python.builtins.objects.floats.PFloat;
-import com.oracle.graal.python.builtins.objects.str.PString;
 import com.oracle.graal.python.nodes.PGuards;
 import com.oracle.truffle.api.dsl.ImplicitCast;
 import com.oracle.truffle.api.dsl.TypeCast;
@@ -48,11 +47,6 @@
 @TypeSystem
 public abstract class PythonArithmeticTypes {
 
-    @ImplicitCast
-    public static String PStringToString(PString value) {
-        return value.getValue();
-    }
-
     @ImplicitCast
     public static double PFloatToDouble(PFloat value) {
         // NOTE: That's correct because we just use it in arithmetic operations where CPython also