[test] Reduce max depthness of nested objects in JSON-stringify.js test.

Modification of InstanceType enum caused JsonStringifier::Serialize_() function
to consume more stack space (because of a switch statement) in non-optimized
debug build which now causes stack overflow on certain depth of nested objects.
The modification affects neither optimized debug nor release builds.

Change-Id: Ia2925d9abbd1c32c5a4694e14c49b2d0bd119419
Reviewed-on: https://chromium-review.googlesource.com/789074
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49657}

test/webkit/resources/JSON-stringify.js

@@ -475,7 +475,7 @@ function createTests() {
     });
     result.push(function (jsonObject){
         var deepObject = {};
-        for (var i = 0; i < 1024; i++)
+        for (var i = 0; i < 1000; i++)
             deepObject = {next:deepObject};
         return jsonObject.stringify(deepObject);
     });
@@ -488,7 +488,7 @@ function createTests() {
     result.push(function (jsonObject){
         var depth = 0;
         function toDeepVirtualJSONObject() {
-            if (++depth >= 1024)
+            if (++depth >= 1000)
                 return {};
             var r = {};
             r.toJSON = toDeepVirtualJSONObject;

test/webkit/run-json-stringify-expected.txt

@@ -499,7 +499,7 @@ function (jsonObject){
 PASS tests[i](nativeJSON) is tests[i](JSON)
 function (jsonObject){
         var deepObject = {};
-        for (var i = 0; i < 1024; i++)
+        for (var i = 0; i < 1000; i++)
             deepObject = {next:deepObject};
         return jsonObject.stringify(deepObject);
     }
@@ -514,7 +514,7 @@ PASS tests[i](nativeJSON) is tests[i](JSON)
 function (jsonObject){
         var depth = 0;
         function toDeepVirtualJSONObject() {
-            if (++depth >= 1024)
+            if (++depth >= 1000)
                 return {};
             var r = {};
             r.toJSON = toDeepVirtualJSONObject;