Fix functools.partial

Fixes #213

Author: msimacek

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/expression/BinaryArithmetic.java

@@ -145,10 +145,11 @@ public abstract static class BinaryArithmeticNode extends BinaryOpNode {
 
         static Supplier<NotImplementedHandler> createHandler(String operator) {
             return () -> new NotImplementedHandler() {
+                @Child private PRaiseNode raiseNode = PRaiseNode.create();
 
                 @Override
                 public Object execute(VirtualFrame frame, Object arg, Object arg2) {
-                    throw PRaiseNode.getUncached().raise(TypeError, getErrorMessage(arg), operator, arg, arg2);
+                    throw raiseNode.raise(TypeError, getErrorMessage(arg), operator, arg, arg2);
                 }
 
                 @CompilerDirectives.TruffleBoundary

graalpython/lib-graalpython/_functools.py

@@ -119,7 +119,7 @@ def __new__(cls, func, /, *args, **keywords):
         if not callable(func):
             raise TypeError("the first argument must be callable")
 
-        if hasattr(func, "func"):
+        if type(func) == partial:
             args = func.args + args
             keywords = {**func.keywords, **keywords}
             func = func.func