DevTools: Show -0 for negative zero in console.

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 12: /^url\(\s*(?:(?:"(?:[^\\\"]|(?:\\[\da-f]{1,6}\s?|\.))*"|'(?:[^\\\']|(?:\\[\da-f]{1,6}\s?|\.))*')|(?:[!#$%&*-~\w]|(?:\\[\da-f]{1,6}\s?|\.))*)\s*\)/i
 CONSOLE MESSAGE: line 13: /^url\(\s*(?:(?:"(?:[^\\\"]|(?:\\[\da-f]{1,6}\s?|\.))*"|'(?:[^\\\']|(?:\\[\da-f]{1,6}\s?|\.))*')|(?:[!#$%&*-~\w]|(?:\\[\da-f]{1,6}\s?|\.))*)\s*\)/i
 CONSOLE MESSAGE: line 12: /foo\\bar\sbaz/i
 CONSOLE MESSAGE: line 13: /foo\\bar\sbaz/i
 CONSOLE MESSAGE: line 12: test
 CONSOLE MESSAGE: line 13: test
@@ skipping 40 matching lines @@
 CONSOLE MESSAGE: line 12: [object Object]
 CONSOLE MESSAGE: line 13: [object Object]
 CONSOLE MESSAGE: line 12: function () {}
 CONSOLE MESSAGE: line 13: function () {}
 CONSOLE MESSAGE: line 12: [object Object]
 CONSOLE MESSAGE: line 13: [object Object]
 CONSOLE MESSAGE: line 12: [object SVGSVGElement]
 CONSOLE MESSAGE: line 13: [object SVGSVGElement]
 CONSOLE MESSAGE: line 12: [object Object]
 CONSOLE MESSAGE: line 13: [object Object]
+CONSOLE MESSAGE: line 12: 0
+CONSOLE MESSAGE: line 13: 0
 CONSOLE MESSAGE: line 12: 
 CONSOLE MESSAGE: line 13: 
 CONSOLE MESSAGE: line 12: function Object() { [native code] }
 CONSOLE MESSAGE: line 13: function Object() { [native code] }
 CONSOLE MESSAGE: line 12: [object Object]
 CONSOLE MESSAGE: line 13: [object Object]
 Tests that console logging dumps proper messages.
 
  Array[10]0: "test"1: "test2"4: "test4"foo: Objectlength: 10__proto__: Array[0] console-format.html:26
 Array[10]0: "test"1: "test2"4: "test4"foo: Objectlength: 10__proto__: Array[0] console-format.html:27
@@ skipping 100 matching lines @@
 globals[23]
 Object {bar: "bar", foo: "foo"}
 <svg id="svg-node"></svg> console-format.html:12
 [svg#svg-node]0: svg#svg-nodelength: 1__proto__: Array[0] console-format.html:13
 globals[24]
 <svg id="svg-node"></svg>
 Object {bar: (...), foo: 1} console-format.html:12
 [Object]0: Objectlength: 1__proto__: Array[0] console-format.html:13
 globals[25]
 Object {bar: (...), foo: 1}
+-0 console-format.html:12
+[-0] console-format.html:13
+globals[26]
+-0
 Object {} console-format.html:12
 [Object]0: Objectlength: 1__proto__: Array[0] console-format.html:13
-globals[26]
+globals[27]
 Object {}
 function Object() { [native code] } console-format.html:12
 [function]0: function Object() { [native code] }length: 1__proto__: Array[0] console-format.html:13
-globals[27]
+globals[28]
 function Object() { [native code] }
 Object {} console-format.html:12
 [Object]0: Objectlength: 1__proto__: Array[0] console-format.html:13
-globals[28]
+globals[29]
 Object {}