Respect quote style in object literals

The option added in fbbaa42ee5 wasn't
being respected inside object literals, so quoted property names would
still be stripped out with this option.

This is mostly a corner-case, but useful when the output is passed to
something like the Closure compiler, where quoted property names can be
used to prevent mangling.

test/run-tests.js

@@ -108,7 +108,11 @@ function run_compress_tests() {
                 expect = test.expect_exact;
             }
             var input = as_toplevel(test.input);
-            var input_code = make_code(test.input, { beautify: true });
+            var input_code = make_code(test.input, {
+                beautify: true,
+                quote_style: 3,
+                keep_quoted_props: true
+            });
             if (test.mangle_props) {
                 input = U.mangle_properties(input, test.mangle_props);
             }