[SMTChecker] User timeout option

test/cmdlineTests/model_checker_timeout_chc/input.sol

@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-3.0
+pragma solidity >=0.0;
+pragma experimental SMTChecker;
+contract test {
+    function f(uint x) public pure {
+		assert(x > 0);
+		assert(x > 2);
+		assert(x > 4);
+    }
+}