Skip Hyp2F1Grad tests in FAST_COMPILE mode

Author: ricardoV94

tests/tensor/test_math_scipy.py

@@ -863,7 +863,10 @@ def test_beta_inc_stan_grad_combined(self):
     op=at.hyp2f1,
     expected=expected_hyp2f1,
     good=_good_broadcast_quaternary_hyp2f1,
-    grad=_good_broadcast_quaternary_hyp2f1,
+    # FIXME: FAST_COMPILE disables C implementation, and the
+    # Elemwise of the fused Hyp2F1 grad loop has more than 32 operands
+    # which is not supported by the python Elemwise perform
+    grad=_good_broadcast_quaternary_hyp2f1 if config.mode != "FAST_COMPILE" else None,
 )
 
 TestHyp2F1InplaceBroadcast = makeBroadcastTester(
@@ -874,6 +877,10 @@ def test_beta_inc_stan_grad_combined(self):
 )
 
 
+@pytest.mark.skipif(
+    config.mode == "FAST_COMPILE",
+    reason="Elemwise of Hyp2F1Grad fails in Python mode due to 32 operand limit",
+)
 class TestHyp2F1Grad:
     few_iters_case = (
         2.0,