Adjusts syntax tests to new constructor syntax.

test/libsolidity/syntaxTests/constructor/constructor_visibility.sol

@@ -0,0 +1,12 @@
+// The constructor of a base class should not be visible in the derived class
+contract A { constructor(string memory) public { } }
+contract B is A {
+  function f() pure public {
+    A x = A(0); // convert from address
+    string memory y = "ab";
+    A(y); // call as a function is invalid
+    x;
+  }
+}
+// ----
+// TypeError: (250-254): Explicit type conversion not allowed from "string memory" to "contract A".