Remove unused state variable in_parameters, and also remove unreachable code (try_an_object always returned an object!)

test/compress/harmony.js

@@ -122,3 +122,14 @@ number_literals: {
         9;
     }
 }
+
+// Fabio: My patches accidentally caused a crash whenever
+// there's an extraneous set of parens around an object.
+regression_cannot_destructure: {
+    input: {
+        var x = ({ x : 3 });
+        x(({ x: 3 }));
+    }
+    expect_exact: "var x={x:3};x({x:3});";
+}
+