testharnessreport: Hide unnecessary elements for JS tests

LayoutTests/http/tests/w3c/webperf/approved/UserTiming/idlharness-expected.txt

-idlharness test
-
-This test validates the WebIDL included in the user Timing specification.
-
-partial interface Performance {
-    void mark(DOMString markName);
-    void clearMarks(optional  DOMString markName);
-
-    void measure(DOMString measureName, optional DOMString startMark, optional DOMString endMark);
-    void clearMeasures(optional DOMString measureName);
-};
-
-interface PerformanceMark : PerformanceEntry {
-};
-
-interface PerformanceMeasure : PerformanceEntry {
-};
-
-
+This is a testharness.js-based test.
 PASS Performance interface: operation mark(DOMString) 
 PASS Performance interface: operation clearMarks(DOMString) 
 PASS Performance interface: operation measure(DOMString,DOMString,DOMString) 
 PASS Performance interface: operation clearMeasures(DOMString) 
 PASS Performance must be primary interface of window.performance 
 PASS Stringification of window.performance 
 PASS Performance interface: window.performance must inherit property "mark" with the proper type (0) 
 PASS Performance interface: calling mark(DOMString) on window.performance with too few arguments must throw TypeError 
 PASS Performance interface: window.performance must inherit property "clearMarks" with the proper type (1) 
 PASS Performance interface: calling clearMarks(DOMString) on window.performance with too few arguments must throw TypeError 
 PASS Performance interface: window.performance must inherit property "measure" with the proper type (2) 
 PASS Performance interface: calling measure(DOMString,DOMString,DOMString) on window.performance with too few arguments must throw TypeError 
 PASS Performance interface: window.performance must inherit property "clearMeasures" with the proper type (3) 
 PASS Performance interface: calling clearMeasures(DOMString) on window.performance with too few arguments must throw TypeError 
 PASS PerformanceMark interface: existence and properties of interface object 
 PASS PerformanceMark interface object length 
 FAIL PerformanceMark interface: existence and properties of interface prototype object assert_equals: class string of PerformanceMark.prototype expected "[object PerformanceMarkPrototype]" but got "[object Object]"
 PASS PerformanceMark interface: existence and properties of interface prototype object's "constructor" property 
 PASS PerformanceMeasure interface: existence and properties of interface object 
 PASS PerformanceMeasure interface object length 
 FAIL PerformanceMeasure interface: existence and properties of interface prototype object assert_equals: class string of PerformanceMeasure.prototype expected "[object PerformanceMeasurePrototype]" but got "[object Object]"
 PASS PerformanceMeasure interface: existence and properties of interface prototype object's "constructor" property 
+Harness: the test ran to completion.