Fix URLSearchParams constructor test

[annevk]

Fixes whatwg/url#220.

[wpt-pr-bot]

Notifying @Sebmaster, @domenic, @mikewest, @rubys, @sideshowbarker, @smola, @tomalec, @xiaojunwu, and @zcorpan. (Learn how reviewing works.)

These tests will be available shortly on w3c-test.org.

• url/urlsearchparams-constructor.html

w3c-test:do-not-mirror (What's this?)

[annevk]

@TimothyGu interested in reviewing?

[wpt-stability-bot]

Chrome (unstable channel)

Testing web-platform-tests at revision e20ac4d
Using browser at version 55.0.2883.75
Starting 10 test iterations
All results were stable

All results

/url/urlsearchparams-constructor.html

Subtest	Results
	OK
Construct with object with two keys	FAIL
URLSearchParams constructor, no arguments	PASS
URLSearchParams constructor, empty string as argument	PASS
Parse %00	PASS
Parse %20	PASS
Parse \0	PASS
URLSearchParams constructor, {} as argument	FAIL
Parse space	PASS
Custom [Symbol.iterator]	FAIL
Basic URLSearchParams construction	PASS
URLSearchParams constructor, DOMException.prototype as argument	FAIL
Constructor with sequence of sequences of strings	FAIL
Construct with object with +	FAIL
Parse +	PASS
Parse 💩	PASS
URLSearchParams constructor, string.	PASS
URLSearchParams constructor, object.	PASS
Parse %e2%8e%84	PASS
Parse %f0%9f%92%a9	PASS
Construct with array with two keys	FAIL
Parse ⎄	PASS

[wpt-stability-bot]

Firefox (nightly channel)

Testing web-platform-tests at revision e20ac4d
Using browser at version BuildID 20170123125947; SourceStamp 36486fdc3813ef7943ae5b07b4128866d1938a6c
Starting 10 test iterations
All results were stable

All results

/url/urlsearchparams-constructor.html

Subtest	Results
	OK
Construct with object with two keys	FAIL
URLSearchParams constructor, no arguments	PASS
URLSearchParams constructor, empty string as argument	PASS
Parse %00	PASS
Parse %20	PASS
Parse \0	PASS
URLSearchParams constructor, {} as argument	FAIL
Parse space	PASS
Custom [Symbol.iterator]	PASS
Basic URLSearchParams construction	PASS
URLSearchParams constructor, DOMException.prototype as argument	FAIL
Constructor with sequence of sequences of strings	PASS
Construct with object with +	FAIL
Parse +	PASS
Parse 💩	PASS
URLSearchParams constructor, string.	PASS
URLSearchParams constructor, object.	PASS
Parse %e2%8e%84	PASS
Parse %f0%9f%92%a9	PASS
Construct with array with two keys	PASS
Parse ⎄	PASS