Remove unused TokenNetwork.max

This reduces the contract size a bit.

raiden_contracts/data/source/raiden/TokenNetwork.sol

@@ -1692,11 +1692,6 @@ contract TokenNetwork is Utils {
         return a > b ? b : a;
     }
 
-    function max(uint256 a, uint256 b) internal pure returns (uint256)
-    {
-        return a > b ? a : b;
-    }
-
     /// @dev Special subtraction function that does not fail when underflowing.
     /// @param a Minuend
     /// @param b Subtrahend

raiden_contracts/data/source/test/TokenNetworkInternalsTest.sol

@@ -281,11 +281,6 @@ contract TokenNetworkUtilsTest is TokenNetwork {
         return min(a,b);
     }
 
-    function maxPublic(uint256 a, uint256 b) public view returns (uint256)
-    {
-        return max(a,b);
-    }
-
     function failsafe_subtractPublic(uint256 a, uint256 b) public view returns (uint256, uint256)
     {
         return failsafe_subtract(a,b);

raiden_contracts/tests/unit/test_unit_internals.py

@@ -22,20 +22,6 @@ def test_min_uses_usigned(token_network_test_utils: Contract) -> None:
             token_network_test_utils.functions.minPublic(a, b).call()
 
 
-def test_max_uses_usigned(token_network_test_utils: Contract) -> None:
-    """ Max cannot be called with negative values """
-
-    INVALID_VALUES = [-UINT256_MAX, -1]
-    VALID_VALUES = [UINT256_MIN, UINT256_MAX, UINT256_MAX]
-
-    all_invalid = chain(
-        product(VALID_VALUES, INVALID_VALUES), product(INVALID_VALUES, VALID_VALUES)
-    )
-    for a, b in all_invalid:
-        with pytest.raises(ValidationError):
-            token_network_test_utils.functions.maxPublic(a, b).call()
-
-
 def test_min(token_network_test_utils: Contract) -> None:
     """ Min works like Python's min """
 
@@ -44,14 +30,6 @@ def test_min(token_network_test_utils: Contract) -> None:
         assert token_network_test_utils.functions.minPublic(a, b).call() == min(a, b)
 
 
-def test_max(token_network_test_utils: Contract) -> None:
-    """ Max works like Python's max """
-
-    VALUES = [UINT256_MIN, 1, UINT256_MAX, UINT256_MAX]
-    for a, b in product(VALUES, VALUES):
-        assert token_network_test_utils.functions.maxPublic(a, b).call() == max(a, b)
-
-
 def test_too_big_runtime_code() -> None:
     compilation = {"TestContract": {"bin-runtime": "33" * 0x6001}}
     with pytest.raises(RuntimeError):