feat(tests): add test cases for P256 input s special values (#2215)

Add test cases for the `p256verify` precompile with `s` edge values:
`1`, `N-1` and `(2**256-1)%N`.
For the last value also include an invalid signature because not covered
by other test cases.

Author: chfast

tests/osaka/eip7951_p256verify_precompiles/test_p256verify.py

@@ -124,6 +124,22 @@ def test_wycheproof_extra(state_test: StateTestFiller, pre: Alloc, post: dict, t
             + Y(Spec.Gy),
             id="hash_max",
         ),
+        pytest.param(
+            H(Spec.N + 1 - Spec.Gx) + R(Spec.Gx) + S(1) + X(Spec.Gx) + Y(Spec.Gy),
+            id="s_1",
+        ),
+        pytest.param(
+            H(Spec.N - 1 - Spec.Gx) + R(Spec.Gx) + S(Spec.N - 1) + X(Spec.Gx) + Y(Spec.Gy),
+            id="s_N_minus_1",
+        ),
+        pytest.param(
+            H(((2**256 - 1) % Spec.N) - Spec.Gx + Spec.N)
+            + R(Spec.Gx)
+            + S((2**256 - 1) % Spec.N)
+            + X(Spec.Gx)
+            + Y(Spec.Gy),
+            id="s_max_mod_N",
+        ),
         pytest.param(
             H(0xC3D3BE9EB3577F217AE0AB360529A30B18ADC751AEC886328593D7D6FE042809)
             + R(0x3A4E97B44CBF88B90E6205A45BA957E520F63F3C6072B53C244653278A1819D8)
@@ -205,6 +221,10 @@ def test_valid(state_test: StateTestFiller, pre: Alloc, post: dict, tx: Transact
             Spec.H0 + Spec.R0 + S(Spec.N) + Spec.X0 + Spec.Y0,
             id="s_eq_to_n",
         ),
+        pytest.param(
+            Spec.H0 + R(Spec.Gx) + S((2**256 - 1) % Spec.N) + X(Spec.Gx) + Y(Spec.Gy),
+            id="s_max_mod_N",
+        ),
         pytest.param(
             Spec.H0 + Spec.R0 + Spec.S0 + X(Spec.P) + Spec.Y0,
             id="x_eq_to_p",