tst_extras crashes on Win 10 CI

Continuous Integration: Failed
 Module "qt/qtquickcontrols" (7cef663456e943135f4382498ba7df7e2a80ee98) Failed test(s): C:/Users/qt/work/qt/qtquickcontrols/tests/auto/extras:
 agent:2016/05/02 10:13:05 build.go:298: Executing instruction 31 of 38
 agent:2016/05/02 10:13:05 build.go:267: [c:\users\qt\MSVC2015.bat jom check] 900 1200
 
 C:\Users\qt\work\qt\qtquickcontrols\tests\auto\extras>call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" amd64  
 
 jom 1.1.0 - empower your cores
 
 	C:\utils\jom\jom.exe -f Makefile.Release check
 	call C:\Users\qt\work\qt\qtquickcontrols\tests\auto\extras\target_wrapper.bat  release\tst_extras.exe -o c:\Users\qt\work\testresults\tests\auto\extras940779784,xml -o -,txt
 ********* Start testing of extras *********
 Config: Using QtTest library 5.6.1, Qt 5.6.1 (x86_64-little_endian-llp64 shared (dynamic) release build; by MSVC 2015)
 PASS   : extras::Tests_CircularGauge::initTestCase()
 PASS   : extras::Tests_CircularGauge::test_instance()
 PASS   : extras::Tests_CircularGauge::test_tickmarksVisible()
 PASS   : extras::Tests_CircularGauge::cleanupTestCase()
 PASS   : extras::Tests_CircularTickmarkLabel::initTestCase()
 PASS   : extras::Tests_CircularTickmarkLabel::test_angleRange()
 PASS   : extras::Tests_CircularTickmarkLabel::test_invalidValues()
 PASS   : extras::Tests_CircularTickmarkLabel::test_labelText()
 PASS   : extras::Tests_CircularTickmarkLabel::test_tickmarksAndLabels()
 PASS   : extras::Tests_CircularTickmarkLabel::cleanupTestCase()
 PASS   : extras::Tests_Common::initTestCase()
 PASS   : extras::Tests_Common::test_resize(CircularGauge)
 PASS   : extras::Tests_Common::test_resize(DelayButton)
 PASS   : extras::Tests_Common::test_resize(Dial)
 PASS   : extras::Tests_Common::test_resize(Gauge)
 jom: C:\Users\qt\work\qt\qtquickcontrols\tests\auto\extras\Makefile.Release [check] Error 2
 jom: C:\Users\qt\work\qt\qtquickcontrols\tests\auto\extras\Makefile [release-check] Error 2
 
 agent:2016/05/02 10:13:34 build.go:206: Process finished with error: exit status 2
 agent:2016/05/02 10:13:34 build.go:158: Error reading from stdout/err: exit status 2
 agent:2016/05/02 10:13:34 agent.go:170: Test failed
 agent:2016/05/02 10:13:34 agent.go:127: ERROR building: Error unmarshalling testlib xml output: EOF
 Build log: http://testresults.qt.io/logs/qt/qtquickcontrols/7cef663456e943135f4382498ba7df7e2a80ee98/WindowsWindows_10x86_64WindowsWindows_10x86_64MSVC2015DebugAndRelease_Release_OpenGLDynamic/e56ba5c15bffe28d5f4d728ce6ebbf447471b101/testrun_1462170544/testlog.txt.gz
 Details: http://testresults.qt.io/coin/integration/qt/qt5/tasks/1462170544.thrift_bin
 Tested changes (refs/builds/qtci/5.6/1462170543):
   https://codereview.qt-project.org/#/q/e40ddf313dfa25d2e9b72f0237d72fc65825a30a,n,z make it actually possible to specify 'ignore' as a class
   https://codereview.qt-project.org/#/q/4e2b6dd3ac794ee81a3865473d99ee3ff3092d60,n,z make it actually possible to exclude classes
   https://codereview.qt-project.org/#/q/34d1464028f28dec2c163c7b595c19c33cf8c3d1,n,z Updated submodules.