improve Dictionary performance (#5202)

- workaround `__proto__` quirks on v8

test/compress/evaluate.js

@@ -3203,7 +3203,7 @@ issue_4552: {
     expect_stdout: "NaN"
 }
 
-issue_4886: {
+issue_4886_1: {
     options = {
         evaluate: true,
         unsafe: true,
@@ -3222,3 +3222,23 @@ issue_4886: {
     }
     expect_stdout: "true"
 }
+
+issue_4886_2: {
+    options = {
+        evaluate: true,
+        unsafe: true,
+    }
+    input: {
+        console.log("foo" in {
+            "foo": null,
+            __proto__: 42,
+        });
+    }
+    expect: {
+        console.log("foo" in {
+            "foo": null,
+            __proto__: 42,
+        });
+    }
+    expect_stdout: "true"
+}

test/compress/objects.js

@@ -198,9 +198,9 @@ numeric_literal: {
     expect_exact: [
         'var obj = {',
         '    0: 0,',
-        '    "-0": 1,',
-        '    42: 3,',
         '    37: 4,',
+        '    42: 3,',
+        '    "-0": 1,',
         '    o: 5,',
         '    1e42: 8,',
         '    b: 7',