Implement __floor__ for float type

Co-authored-by: Tetramad <cbwjd777@gmail.com>

Lib/test/test_float.py

@@ -324,8 +324,6 @@ class GeneralFloatCases(unittest.TestCase):
         # distinguishes -0.0 and 0.0.
         self.assertEqual((a, copysign(1.0, a)), (b, copysign(1.0, b)))
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_float_floor(self):
         self.assertIsInstance(float(0.5).__floor__(), int)
         self.assertEqual(float(0.5).__floor__(), 0)

vm/src/builtins/float.rs

@@ -389,6 +389,11 @@ impl PyFloat {
         try_bigint(self.value, vm)
     }
 
+    #[pymethod(magic)]
+    fn floor(&self, vm: &VirtualMachine) -> PyResult<BigInt> {
+        try_bigint(self.value.floor(), vm)
+    }
+
     #[pymethod(magic)]
     fn ceil(&self, vm: &VirtualMachine) -> PyResult<BigInt> {
         try_bigint(self.value.ceil(), vm)