Fixes bug when $location.search() is not returning search part of current url. Inluding tests.

[bullgare]

The issue appears when we set $location.search() with some object and after that change this object's properties, like that:

var obj = {foo: 'bar'};
$location.search(obj); // now url is set to '#?foo=bar'
obj.foo = 'boo';
var currentUrlObj = $location.search();
// current location is still '#?foo=bar' 
// while currentUrlObj is telling that current url object is {foo: 'boo'}
// which isn't correct

There's a little demo onJSBin:
http://jsbin.com/rekana/5/edit?js,output
And another JSBin with behaviour fixed on consumer's side:
http://jsbin.com/rekana/1/edit?js,output
I'm sure it's a bad idea to make someone think of that on the consumer's side.

[bullgare]

@caitp could you please code review this.
It's a copy of this request #9410 where I had some problems with merge.

[bullgare]

@caitp could you please make a code review.

[caitp]

I wonder if we should no-op when the passed search object is the same as the one returned from search(), since it would be pointless work

[caitp]

lgtm, but I would add the no-op in the case I mentioned

[caitp]

if (search === this.$$search) return this;

[caitp]

@IgorMinar wdyt? I don't think it's a bug that hit's everyone, but it seems kinda buggy to me

[IgorMinar]

Lgtm