DevTools: Change RemoteObject._describe method for Errors

LayoutTests/inspector/console/console-format-expected.txt

 CONSOLE MESSAGE: line 26: test,test2,,,test4,,,,,
 CONSOLE MESSAGE: line 27: %o
 CONSOLE MESSAGE: line 28: %O
 CONSOLE MESSAGE: line 29: Test for zero "%f" in formatter
 CONSOLE MESSAGE: line 30: %% self-escape1
 CONSOLE MESSAGE: line 31: %%s self-escape2
 CONSOLE MESSAGE: line 32: %%ss self-escape3
 CONSOLE MESSAGE: line 33: %%s%s%%s self-escape4
 CONSOLE MESSAGE: line 34: %%%%% self-escape5
 CONSOLE MESSAGE: line 35: %%%s self-escape6
@@ skipping 92 matching lines @@
 globals[2]
 "test"
 test named "test" console-format.html:12
 ["test named "test""] console-format.html:13
 globals[3]
 "test named "test""
 Error {stack: (...)}stack: (...)get stack: function () { [native code] }set stack: function () { [native code] }__proto__: d console-format.html:12
 [Error]0: Errorlength: 1__proto__: Array[0] console-format.html:13
 globals[4]
 Error {stack: (...)}stack: (...)get stack: function () { [native code] }set stack: function () { [native code] }__proto__: d
-Error {stack: (...), message: "my error message"}message: "my error message"stack: (...)get stack: function () { [native code] }set stack: function () { [native code] }__proto__: d console-format.html:12
-[Error]0: Errorlength: 1__proto__: Array[0] console-format.html:13
+Error: my error message {stack: (...), message: "my error message"}message: "my error message"stack: (...)get stack: function () { [native code] }set stack: function () { [native code] }__proto__: d console-format.html:12
+[Error: my error message]0: Error: my error messagelength: 1__proto__: Array[0] console-format.html:13
 globals[5]
-Error {stack: (...), message: "my error message"}message: "my error message"stack: (...)get stack: function () { [native code] }set stack: function () { [native code] }__proto__: d
+Error: my error message {stack: (...), message: "my error message"}message: "my error message"stack: (...)get stack: function () { [native code] }set stack: function () { [native code] }__proto__: d
 <p id="p">Tests that console logging dumps proper messages.</p> console-format.html:12
 [p#p]0: p#plength: 1__proto__: Array[0] console-format.html:13
 globals[6]
 <p id="p">Tests that console logging dumps proper messages.</p>
 function () { return 1; } console-format.html:12
 [function]0: function () { return 1; }length: 1__proto__: Array[0] console-format.html:13
 globals[7]
 function () { return 1; } console-format.html:45
 function () {
         return 2;
@@ skipping 93 matching lines @@
 function () {} console-format.html:62
 Number {[[PrimitiveValue]]: 42} console-format.html:12
 [Number]0: Numberlength: 1__proto__: Array[0] console-format.html:13
 globals[31]
 Number {[[PrimitiveValue]]: 42}
 String {0: "a", 1: "b", 2: "c", length: 3, [[PrimitiveValue]]: "abc"} console-format.html:12
 [String]0: Stringlength: 1__proto__: Array[0] console-format.html:13
 globals[32]
 String {0: "a", 1: "b", 2: "c", length: 3, [[PrimitiveValue]]: "abc"}