Sort tests.

test/libsolidity/semanticTests/various/gasleft_decrease.sol

@@ -0,0 +1,20 @@
+contract C {
+    uint256 v;
+
+    function f() public returns (bool) {
+        uint256 startGas = gasleft();
+        v++;
+        assert(startGas > gasleft());
+        return true;
+    }
+
+    function g() public returns (bool) {
+        uint256 startGas = gasleft();
+        assert(startGas > gasleft());
+        return true;
+    }
+}
+
+// ----
+// f() -> true
+// g() -> true