Adjusts syntax tests to new constructor syntax.

test/libsolidity/syntaxTests/constructor/constructor_state_mutability.sol

@@ -0,0 +1,9 @@
+contract test1 {
+  constructor() public view {}
+}
+contract test2 {
+  constructor() public pure {}
+}
+// ----
+// TypeError: (19-47): Constructor must be payable or non-payable, but is "view".
+// TypeError: (69-97): Constructor must be payable or non-payable, but is "pure".