fix(minErr): stringify non-JSON compatible objects in error messages

Fix the JSON stringification to output a more meaningful string when an
object cannot be normally converted to a JSON string, such as when the
object contains cyclic references that would cause `JSON.stringify()`
to throw an error.

Closes #10085

test/.jshintrc

@@ -18,6 +18,7 @@
     "angularModule": false,
     "nodeName_": false,
     "uid": false,
+    "toDebugString": false,
 
     "lowercase": false,
     "uppercase": false,

test/minErrSpec.js

@@ -60,6 +60,13 @@ describe('minErr', function() {
         toMatch(/^\[test:26\] false: false; zero: 0; null: null; undefined: undefined; emptyStr: /);
   });
 
+  it('should handle arguments that are objects with cyclic references', function() {
+    var a = { b: { } };
+    a.b.a = a;
+
+    var myError = testError('26', 'a is {0}', a);
+    expect(myError.message).toMatch(/a is {"b":{"a":"<<already seen>>"}}/);
+  });
 
   it('should preserve interpolation markers when fewer arguments than needed are provided', function() {
     // this way we can easily see if we are passing fewer args than needed

test/stringifySpec.js

@@ -0,0 +1,15 @@
+'use strict';
+
+describe('toDebugString', function() {
+  it('should convert its argument to a string', function() {
+    expect(toDebugString('string')).toEqual('string');
+    expect(toDebugString(123)).toEqual('123');
+    expect(toDebugString({a:{b:'c'}})).toEqual('{"a":{"b":"c"}}');
+    expect(toDebugString(function fn() { var a = 10; })).toEqual('function fn()');
+    expect(toDebugString()).toEqual('undefined');
+    var a = { };
+    a.a = a;
+    expect(toDebugString(a)).toEqual('{"a":"<<already seen>>"}');
+    expect(toDebugString([a,a])).toEqual('[{"a":"<<already seen>>"},"<<already seen>>"]');
+  });
+});